I still have a Packard Bell 486 restore CD and have always been curious how it would verify that it was a Packard Bell ever since I was a young person.
But I've never dug into how to bypass this, because I've always had the opposite preference of wanting a clean install.

In modern-ish times DMI would be a standardized way to figure out whether the machine is a Compaq (or whatever). I don't know if that was already used in the early 2000s.
Before that, I suspect they used heuristics like checking the BIOS copyright string and sign-on message.

Rather than trying to bypass the check, it might be more fruitful to figure out if the restore discs have a compressed disk image in some format that could be recoverable without actually running them--I suspect the software on these discs was probably outsourced to a handful of companies (something like a runtime-only version of Norton Ghost, for example) so there wouldn't be that many formats.

I never looked into this in detail, but in what experience I do have looking at it (still having a number of "restore CDs" for systems that are long gone)... I had the impression that the OEM systems each have a custom BIOS which has a "special" string in it somewhere which is read by the installer to verify that the system is "legit". It may also involve looking for a bit of hardware that's not expected to change with future editions of the machine (manufacturers don't want to spend money arranging new Winblows CDs due to a small hardware update).

This can vary a fair bit - I've got some restore CDs which won't proceed on anything but the EXACT system they were made for, not even differing ones by the same manufacturer.

On the other hand I have a few Dell OEM Win7 CDs (I did some work for a company that ran Linux on "new" Dells and often found the unused Winblows install CDs in the garbage) - I've since gotten at least 5 Dell machines and these installs always work (and the machines are quite different from each other = I7, I5, I3, Pentium, different on-board peripherals, full and small form factor (so very different mainboards) etc. - there's even at least one the CD doesn't have all the drivers for and I have to install drivers after ... but the OS still installs even though it was obviously not made for this exact system)

My advise: Just use a "standard" Win98 retail/general install CD and scrounge up any extra drivers you might need.
I would think that trying to "bypass" vendor system verification is not going to be easy - obviously Microsoft would have wanted the OEMs to have fairly robust protection in place to prevent exactly this kind of thing!

The Packard Bell restore cd from 1996 I use to have, identified the system off of the atapi cd-rom drive id.

Many Compaq and IBM OEM restore disks checked the BIOS for identification.

Thanks guys for the answers, I just wanted to recreate the same system, which most of the time have a good amount of additional software, which retail versions won't have.

akimmet wrote on Yesterday, 23:20:

The Packard Bell restore cd from 1996 I use to have, identified the system off of the atapi cd-rom drive id.

Interesting. So hopefully your CD-ROM drive doesn't fail...
On the other hand, that's conducive to fixing in your emulator easily.