Yeah, I'd thought of that, and done periodic on-demand scans on this machine in the past few weeks, despite the fact that
I've got company wide McAffee VirusScan running 24/7 on all machines reporting to a central console and auto-updating the .dat files weekly.

Also, what virus would cause damage that would cause an I/O timeout in DR-DOS (Maxblast II's OS) while doing an image copy?

It just didn't seem viral.

Some other tidbits: the drive was only 1/2 full (4.5 of 10 GB) and had been defragged with no effect.

The drive speed change was gradual. It just got slower & slower until the machine really became unusable.

-Zeke