Can you suggest what else I should try?
Replaced the Hard Drive for a person's system:
Motherboard: ABIT WB6
Processor: Pentium II- 366
RAM: one 128M PC-100
Primary IDE master: Seagate 80G (new)
Secondary IDE master: Mitsumi 48x CD-ROM
The problem is that after installing Windows 98SE, when installing Adobe Acrobat Reader 5, the installation stops with "corrupt cab file" (even it installs flawlessly from the same CD on every other system); and then DirectX 9.0b halts when it installs. Since the files were copied first onto the hard drive from the CD-ROM, I thought there could be a problem with the CD-ROM, but in trying a different CD-ROM and a different secondary cable, re-setting up Windows, same problem.
I ran Seagate diagnostics on the new hard drive. No problems.
I tried to set up Windows XP on the system. Everything loaded ok except for an error loading "System" but it all progressed. Adobe Acrobat Reader 5 installed fine, but DirectX 9.0b (downloaded from the internet) could not install.
I tried a different HD and a different primary cable, same problem.
BIOS for motherboard is already the latest available version.
I have Microscope version 11, I ran systemboard and memory diagnostics, no problems.
Have tried several of the BIOS settings, shutting on and off HD block mode, trying the fail-safe defaults, and the optimized defaults, no difference, same problem. I could try more in this area but I don't really have a sense of which timing settings are most likely to make a difference.