PC Stalling.. PSU to blame?

[Naffa]

im pretty sure its to do with my PSU.. ummm its an e"Competitor" value PSU

basically my PC has started stalling randomly and as i said im pretty sure its my rubbish psu but just to be sure, im asking. my PC stalls after leaving it on for a few hours then coming back to it. i come back and start to use it again and it stalls and i have to restart.

when i built my rig i was unaware of the importance of a decent PSU, now i am

heres my spec:

A64 3500+ @ 2.53Ghz
1GB OCZ Value DDR PC3200
ATi Radeon X1800XT 512MB
500W Generic PSU

is my rubbish PSU the problem?

 

[Naffa]

all temps are ok and i dont have a decent psu to test other than a 400W Q-Tec in a rig that was given to me but i think il take my chances with the generic

 

[Naffa]

alright, il do that