can u access bio at all ?
change your first boot drive to "cdRom" and chuck the XP cd in the drive. It will ask u on start up if u wont to run cd, by pressing any key. u can foramtt through there if u can get it to that stage, or change it in bios.
im not sure thats what i do anyways. if it dont work then im stumped, mine has never locked up on me before.
Amd Athlon 2400+
GeXcube Radeon 9600 XT Xtreme (overclocked)
King Max 512 (3200)
SamSung 52x32x52 CD-RW