When I tried to boot from the IBM Aptiva Master CD, it came up with, Incorrect BIOS Version.

Do you have any suggestions?

Suggestion: Buy an IBM Aptiva PC. The way these pre-XP OEM restore discs usually work is they check they BIOS for a special signature. If they find the signature, then they continue to boot and restore the OS as intended. If not, toss an error up on the screen and refuse to do anything. Virtual PC doesn't have this special BIOS signature, so no pre-XP OEM recovery CD will work in it.

Small additional note. It's not just pre-XP OEM discs that do something like that. I tried to install Vista on my spare drive once with the discs from a Toshiba U205 laptop, and it refused to install because I wasn't using the proper computer model.

I ran into this problem trying to install an olivetti envision version of Windows 95 and also a compaq version of windows 98, nothing to do as linuxlove said, even trying to boot via floppy or trying to install from an installed version od dos...

If it's possible to crack the archives, then you could restore the contents of the CD-ROM itself without using the prebundled restore utility.

That being said, I myself have been able to crack the .ZIP files manually with a December 1995 version of the IBM Aptiva PS/1 Recovery CD-ROM (with no utilities either, just examining the contents of one of the .EXE files, only to find the command to extract the .ZIP archives using PKUNZIP), so if that's possible, then you should be able to load the contents of the CD-ROM itself onto a virtual hard disk within a virtual machine; the only problem that you would have from that point on would be with the default drivers supplied by IBM, which would most likely be incompatible with the hardware used by Virtual PC itself.

Did the same with a '97 Aptiva disk, extracted about 30 archives with the password found on a forum, just by googling the name of the disk, and it was the same for all the IBM's CDs a the time...

The password was: magic

If you're lucky, they may have kept it