Computer rebooting all the time, plz help

[zak2501]

recently my computer has been rebooting.
I am using windows xp pro on my computer. It reboots wen in windows, it doesnt matter wat im doing.
and after it does it keeps rebooting b4 windows even starts. my power supply is only a month old and same with my cpu fan. temp is always normal. ive tried different video cards, hard drives, and swapping RAM around. ive ran a memtest but it restarted after like 12 hrs of testing. Sometimes my computer works for 2 days b4 it restarts agian and goes into a loop of restarting b4 windows loads. i formated my comp and currently installing windows on another computer because i cant even install windows without it restarting.
computer consists of 5 fans all working fine, 3 fans have been replaced recently.
specs: AMD Athelon 2100+
512ram pc2100 ddr
power supply : ATX 300w
mobo : gigbyte ga-7vax via kt400
wester digital 40 gig 100gig
geforce 4 ti 4800
sound blaster live
win xp pro
poineer dvd burner
pc has been custom built

im sorry if i posted this in the wrong forum.
help would be very much appreciated, thx for ur time

 

[S0Y73NTGR33N]

Hmm... I had a computer powering on and off at work today, replaced power supply and RAM and still did it. I would say motherboard is bad.

Try putting each component in this PC into another and if the problem never replicates then I'd check CPU and mobo out.


-green

 

[zak2501]

my other computer wont take this kind of ram
but im starting to think something is wrong with the mobo or cpu
they are both a year old

 

[montag451]

can you check the temps of your cpu?

 

[zak2501]

temps are
system: 50C
cpu: 56C
cpu fan speed 4326 rpm
both these fans are only a month old.
i just formatted and reinstalled windows, that didn't work it still restarts.