I encountered this same problem while installing XP on a new PC (during the Windows XP setup, the PC would restart at "Installing Devices" every time), and I found this (very old) page while attempting to troubleshoot it. My issue was actually caused by bad memory timings, not unsigned drivers. After I went into my BIOS and relaxed my memory timings, the Windows installer worked without a problem. I just wanted to post this alternet solution, in case anyone else comes across this problem and also finds this thread.
FYI, the page that led me to a fix is here:
http://www.houseofhelp.com/v3/showthread.php?t=72523
I'd purchased Corsair TWIN2X2048-6400C4 DDR2 RAM, which was advertised as being rated for 4-4-4-12 timings, so I set these manually in my motherboard BIOS (an Intel DG45ID). Unfortunately, Corsair does not make it clear that their memory is only rated for those timings at increased voltage (1.9v). After I set the timings back to the default (5-5-5-18), the Windows XP setup completed successfully.