Switched cables, same line, so its the monitor.
Tonight: unplugged the hard drive, plugged in a new Corsair Force 3 GS 240 GB SSD, installing XP now.
If all goes well, I'll update the drivers for the printer, scanner, and remaining graphics card.
Then I'll see about plugging in the original HD and see if I can access it. Last time I did this, I had to set the old HD to slave.
When I get it going, I'll add a 3rd HD, a new WD Black 1 TB and copy the files from the original.
Setup is proudly telling me that "Windows XP is the easiest Windows yet".