I've been given a system to repair, the symptom being that it will not boot
past the blue XP splash screen with the Windows logo. It won't work in
normal or safe mode.

Any suggestions?

MikeP wrote:
Diagnose drives and memory.

Yank out all nonessensial cards, and drives,and disable the built in
stuff. A bad device could be causing the hangup. You can either
disable/unplug one at a time, until it boots or disable them all at
once and reenable them till it hangs again.