Hello thank you for any 1 helping me in my problem.

Ok my problem is i just gotta new system:-
ABIT kt7a RAID
Fujitsu 20 gig
Soundblaster live 5.1
56k modem
dvd player
cdrw
256 ram 133
athlon 1.400 -266-

my system would just reboot automacticly after about 1 hour it just shuts off and reboots i had problems with IRQs on the soundblaster i thought it was that but still not sure and then thought it was cause maybe it was overheatin but got good cooler and now its runnin cool now so im out of ideas plz plz help me