We are having the same problem with a Dell P-566, it crashed one day after having no problems for several months. The error message is: "While initializing device IOS, windows protection error, You must restart...." now it will not even start in safe mode and, can't get past the first part of the win98 install.
Sometimes the error message says "while initializing device configmg" or "device vgartd....".
Interestingly, it will boot to the command promt only, and the hardware diagnostic CD found no problems. A new hard drive seemed to work but eventually that crashed.
The next thing we will try is new memory, or a new motherboard, and hopefully one of those will fix it.