My recommendations, in this order, are :

a) Inspect motherboard and video card capacitors
b) What PSU are you using and if it is an older one, how are its capacitors ?
c) Memtest the RAM (it is unclear whether you tried 2 different DIMMs or just removed one to go from 512MB to 256MB, if you used completely different RAM in both tests then a RAM issue is unlikely)
d) Remove all non essential add-on cards (sound, card, SCSI, TV card) you can put them in one by one once you have Windows installed .

Good luck!

EDIT : As you probably know, capacitors can fail without showing .

That error message is sounds like ressource conflicts. Id recommend you to remove everything from the computer except for the video card and try it then.

johnyept wrote on 2021-03-29, 01:55:

Windows Protection Error. I can run it in safe mode, but that's it. If I use Windows 98 SE fdisk, it creates a 48GB partition instead of 120GB, but the end result is the same.

No ! Win98se is old school 32 bit FAT and you need to make a less than 32GB C: , even XP cannot boot off a <32Gb FAT partition w/o error.
This has to due with the old 32bit FAT boot partition size, not the drive size. fixed some of my boo-booo

Horun wrote on 2021-03-29, 02:32:

johnyept wrote on 2021-03-29, 01:55:

Windows Protection Error. I can run it in safe mode, but that's it. If I use Windows 98 SE fdisk, it creates a 48GB partition instead of 120GB, but the end result is the same.

No ! Win98se is old school 32 bit FAT and you need to make a less than 32GB C: , even XP 32bit cannot boot off a <32Gb FAT partition w/o error.
This has to due with the old 32bit boot partition size, not the drive size the OS can see.

AFAICR, Windows 98 SE's ESDI_506.PDR (generic IDE driver) works fine with drives up to LBA28 limits (136902082560 bytes or just over 127GB) . Even Microsoft says so https://docs.microsoft.com/en-us/previous-ver … n-fat32-volumes .

As for ability to boot from a large partition, I initially installed Windows 98 SE to a 1TB hard drive (using a patched ESDI_506.PDR to overcome the drive size limit issue, a patch would not have been necessary if using a controller whose driver is not based on ESDI_506.PDR and supports LBA48), and no other patches were required to install and boot successfully to a 120GB FAT32 boot partition .

darry wrote on 2021-03-29, 03:01:

Horun wrote on 2021-03-29, 02:32:

johnyept wrote on 2021-03-29, 01:55:

Windows Protection Error. I can run it in safe mode, but that's it. If I use Windows 98 SE fdisk, it creates a 48GB partition instead of 120GB, but the end result is the same.

No ! Win98se is old school 32 bit FAT and you need to make a less than 32GB C: , even XP 32bit cannot boot off a <32Gb FAT partition w/o error.
This has to due with the old 32bit boot partition size, not the drive size the OS can see.

AFAICR, Windows 98 SE's ESDI_506.PDR (generic IDE driver) works fine with drives up to LBA28 limits (136902082560 bytes or just over 127GB) . Even Microsoft says so https://docs.microsoft.com/en-us/previous-ver … n-fat32-volumes .

As for ability to boot from a large partition, I initially installed Windows 98 SE to a 1TB hard drive (using a patched ESDI_506.PDR to overcome the drive size limit issue, a patch would not have been necessary if using a controller whose driver is not based on ESDI_506.PDR and supports LBA48), and no other patches were required to install and boot successfully to a 120GB FAT32 boot partition .

I have never had good luck hacking/patching the Win98/XP to boot from greater than 32GB C: under FAT32. Max size of partition FAT32 is different than max size of boot partition of Windows under FAT32.

The size of the partition doesn't matter. I am using a computer with a 111gb partition FAT32 just fine.

I have received the windows protection error when I have too much memory installed. For me it was 768mb of SDRAM... going down to 512MB and doing nothing else fixed the issue.

Horun wrote on 2021-03-29, 02:32:

johnyept wrote on 2021-03-29, 01:55:

Windows Protection Error. I can run it in safe mode, but that's it. If I use Windows 98 SE fdisk, it creates a 48GB partition instead of 120GB, but the end result is the same.

No ! Win98se is old school 32 bit FAT and you need to make a less than 32GB C: , even XP cannot boot off a <32Gb FAT partition w/o error.
This has to due with the old 32bit FAT boot partition size, not the drive size. fixed some of my boo-booo

I’ll second that.
Had the same problem with a 40gb hard drive using a single partition. Issue was solved by using partitions smaller than 32GB.

darry wrote on 2021-03-29, 02:01:

d) Remove all non essential add-on cards (sound, card, SCSI, TV card) you can put them in one by one once you have Windows installed .

I would be much more inclined to look for problems here than to start looking at partition sizes.

It is also often useful to try booting a Live version of Linux to rule out obvious hardware problems. (Puppy Linux should be fine.) If Linux doesn't work, that could just mean that Linux has different problems – but if it does work, then that might rule out particularly egregious hardware conflicts.

Horun wrote on 2021-03-29, 03:15:

darry wrote on 2021-03-29, 03:01:

Horun wrote on 2021-03-29, 02:32:

No ! Win98se is old school 32 bit FAT and you need to make a less than 32GB C: , even XP 32bit cannot boot off a <32Gb FAT partition w/o error.
This has to due with the old 32bit boot partition size, not the drive size the OS can see.

AFAICR, Windows 98 SE's ESDI_506.PDR (generic IDE driver) works fine with drives up to LBA28 limits (136902082560 bytes or just over 127GB) . Even Microsoft says so https://docs.microsoft.com/en-us/previous-ver … n-fat32-volumes .

As for ability to boot from a large partition, I initially installed Windows 98 SE to a 1TB hard drive (using a patched ESDI_506.PDR to overcome the drive size limit issue, a patch would not have been necessary if using a controller whose driver is not based on ESDI_506.PDR and supports LBA48), and no other patches were required to install and boot successfully to a 120GB FAT32 boot partition .

I have never had good luck hacking/patching the Win98/XP to boot from greater than 32GB C: under FAT32. Max size of partition FAT32 is different than max size of boot partition of Windows under FAT32.

The "hack" is because I am using a driver bigger than ESDI_506.PDR allows (greater than 127GB) . No patch is necessary for the boot partition.

If I was using a drive smaller than 127GB and using a single FAT32 boot partition that cover the entire disk, not patch would be necessary at all (except that the included Fdisk borks with drives greater tahn 64GB, but there is a hotfix here https://www.betaarchive.com/wiki/index.php?ti … _Archive/263044 or I could just not use Fdisk to do the partitioning), AFAIK (pretty sure I ran Windows 98 SE on such a setup a long while back). Additionally, I can't find any reference to a specific boot partition size limit versus a non boot partition size limit for Windows 98 SE (either here https://www.betaarchive.com/wiki/index.php/Mi … soft_KB_Archive or in my memory) . I will have to test this again sometime .

Incidentally, Windows 95 does have a 32GB hard limit for disk size (and likely partition size as well, though there may also be other limitations I don remember) https://www.betaarchive.com/wiki/index.php?ti … _Archive/246818

there exist updated fdisk and format that fixes the bug. search mdgx for them probably can't post it here. thered also a patcher that rloew created to patch 98se io sys that fixes all the issues with larger drives I can probably post that. since its a patcher not a binary.

I've installed Windows 98 SE to plenty of 120 gigabyte SSDs with one partition with no issues. Just did it yesterday.

Repo Man11 wrote on 2021-03-29, 04:00:

I've installed Windows 98 SE to plenty of 120 gigabyte SSDs with one partition with no issues. Just did it yesterday.

Same. I use the version of fdisk that comes on the install CD. Never one time had an issue.

I've seen it plenty of times vanilla FDISK not seeing all 137 gbs or whatever the max is.

Proof
http://web.allensmith.net/Storage/HDDlimit/98Fdisk.htm

The updated fdisk format obsoletes this patch btw. By fixing a display bug that truncates the size to 5 digits.

Essentially the MS patch + display bug fix.

More info

https://msfn.org/board/topic/85573-corrected- … isk-and-format/

This doesn't always bug out on all hard drives of computers but it does bug out sometimes on some hdds etc

Warlord wrote on 2021-03-29, 04:09:

I've seen it plenty of times vanilla FDISK not seeing all 137 gbs or whatever the max is. […]
Show full quote

I've seen it plenty of times vanilla FDISK not seeing all 137 gbs or whatever the max is.

Proof
http://web.allensmith.net/Storage/HDDlimit/98Fdisk.htm

The updated fdisk format obsoletes this patch btw. By fixing a display bug that truncates the size to 5 digits.

Essentially the MS patch + display bug fix.

More info

https://msfn.org/board/topic/85573-corrected- … isk-and-format/

This doesn't always bug out on all hard drives of computers but it does bug out sometimes on some hdds etc

FDISK reports the wrong size but it partitions the drive just fine. It is only really an issue if you don't want to partition the drive as a single partition.

Ok, went to sleep after the post and woke up to 14 replies 🤣

So, instead of adding several quotes, I'll try to answer everything from the 1st reply down:

- Motherboard and video card capacitors "seem" fine, I did test with another video card so it could be the board, although it only stops at the error protection, and no other symptom is visible. I think I have one or two other identical boards, so if it all fails I'll test with those ones
- The PSU is old, I have a new one and will try with that one later tonight
- I'm only using one stick of RAM, so I tried with 1x512MB and 1x256MB, I did not try Memtest but I do have several sticks and all the ones I tested worked well up to the error protection, so it would be a huge coincidence that they all ended up in the same error
- As suggested, I'll remove all extra hardware and try to install Windows with only the board, a <=30GB HDD, CD and floppy. I should have used a lighter tower, this tower is heavy as s**t and hard to handle, a test bench would be ideal but that is last on the bucket list...
- I have a patched ESDI_506.PDR but I didn't use it yet, Windows installed fine on a P4 3.2Ghz with a 80GB HDD, but different boards and different HDDs so different symptoms and all that, so I'll leave it to last
- I usually create a single partition with Hiren's Boot CD and XP's Disk Management to avoid those exact problems with fdisk and format, and because they are slooooooooooow as hell, but I did try with those as well which created and formatted a 48GB partition and ended up with the same error, so it's probably not the partition size, but might be a BIOS limitation somehow, I'll verify that theory with a 20GB HDD

Testing will begin in 11 hours...

EDIT: to "fix" the fdisk/format problem, I'll try Free FDisk 1.2.1 which supports HDDs up to 128GB, and Windows Me Format which correctly formats the partition, although it might still display wrong numbers.

Well, I found the culprit...

Yesterday it was already very late and I was frustrated and out of patience. Today I removed every single piece of hardware except for one HDD, DVD and floppy drive, and Windows opened up straight to the desktop. Ummm... I started adding piece by piece and testing it out, and after adding everything back in except for the SCSI cable from the CD to the card, Windows was still booting fine. Then I connected the SCSI cable to the card, and Windows took longer to boot, but for some reason re-detected and re-installed the SCSI card drivers and this time the card had an exclamation mark. So I removed it, re-inserted it, and voila, Windows Protection Error! So the culprit was a bad connection with the SCSI card!
I cleaned its contacts, reinstalled Windows 98 SE using the full 120GB HDD and I now have a working Windows 98 SE with a bunch of old hardware I can now play around with! I hope the HP Colorado tapes still work, I want to see what I stored in them over 20 years ago 😉

Thanks for all the replies and suggestions, I was certain we would make it boot once again, in one way or another!

johnyept wrote on 2021-03-29, 20:42:

Well, I found the culprit... the culprit was a bad connection with the SCSI card!

Great ! Good work.

darry wrote on 2021-03-29, 03:51:

Incidentally, Windows 95 does have a 32GB hard limit for disk size (and likely partition size as well, though there may also be other limitations I don remember) https://www.betaarchive.com/wiki/index.php?ti … _Archive/246818

Yes you are right ! It was late and was thinking Win95 not Win98. I have had issues dual-booting XP and DOS 7 on greater than 32Gb Boot partition but that could have been a hardware specific thing but happened on both a soc478 and soc775 but that is a diff topic.