This appears to be phil's easy MS-DOS mode shortcut - You must have been experimenting with it before you left the computer for a while. That means your normal config.sys/autoexec.bat files were copied to a backup and temporarily replaced with the easy MS-DOS shortcut settings (windows does this automatically as part of the MS-DOS application compatibility system). It normally would revert those changes when you go back into windows by running win and answering y. It's likely that having both the regular DOS boot (BootGUI=0) method and the ms-dos mode shortcut may have conflicted.

If you look at your C drive, there should be a copy of your original DOS start files as like config.wos and autoexec.wos. If you restore those to their original name it should go back to how it was. Always keep a copy of your current files in case you make things worse (eg rename current config.sys and autoexec.bat to filename.bak or something) and don't reboot the computer until all files are in place with their correct names.

Off topic, but is it really a Sun display ?
Maybe from a Blade or circa 2000, I don't think previous had VGA input.

nali wrote on 2026-02-11, 22:46:

Off topic, but is it really a Sun display ?
Maybe from a Blade or circa 2000, I don't think previous had VGA input.

Yes, Sun GDM-5410 with one vga input and built in 13w3 cable. Got it for free off craigslist a couple years ago. 😀

^^ thank you, @NeoG_. I'll give your suggestions a try today. Amd, you've jogged my memory further. Yes, it is Phil's easy ms-dos. I believe I had previously been booting into windows bu default and then using the easy ms-dos shortcut for dos action....but had forgotten about that in the months of non-action. When revisiting the pc, I booted into windows then rebooted into dos via the crrl-alt-del restart menu method.

Will report back later today.

YesAffinity wrote on 2026-02-13, 14:03:

Got it for free off craigslist a couple years ago. 😀

I'm jealous ! 😀
I had a complete Sun IPC 25MHZ, with flat display, optic mouse, external tape, external cdrom and external disk, but gave it to a friend when I moved from France to Canada.
Nice machine, it ran NetBSD perfectly.

nali wrote on 2026-02-13, 17:54:

I'm jealous ! :) I had a complete Sun IPC 25MHZ, with flat display, optic mouse, external tape, external cdrom and external disk […]
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YesAffinity wrote on 2026-02-13, 14:03:

Got it for free off craigslist a couple years ago. 😀

I'm jealous ! 😀
I had a complete Sun IPC 25MHZ, with flat display, optic mouse, external tape, external cdrom and external disk, but gave it to a friend when I moved from France to Canada.
Nice machine, it ran NetBSD perfectly.

Very nice! This Sun monitor is on a VGA 4x4 matrix, with DOS/98, XP/7 and Win 11 PC's on it, along with various retro game consoles and scalers that can all be routed into it for wonderful 4:3 or 5:4 hi res goodness. It will even reconcile 720p and 1080p, but the image will be a bit out of proportion and no guarantee I can get it to fill out the extents via the OSD menu.

Back to the topic at hand... 😀

I figured out what I did, and have restored this DOS/98 PC to full functionality. The reminder about Phil's easy dos shortcut was the memory trigger I needed. I refreshed on how that works (watched Phil's video), and then undid what I had done when I revisited this PC. When it wasn't booting right, I had replaced autoexec.bat and config.sys with my backup DOS versions. Those of course should be empty files for Windows and the Phil's easy DOS PIF handles all that when restarting into "easy DOS mode". Fortunately, I have a backup of the hard drive on a CF flash, and once confirming the contents of autoexec.bat and config.sys should be empty, I edited them accordingly within DOS on the PC, rebooted, and all is working as intended (or at least as engineered by me). 😀

Now off to play some Zork in DOS, which is what sent me down this path in the first place. Thanks for the help @NeoG_, and good chatting @nali!