hi all. ok so i got this pc up and running today so i was reinstalling windows xp on it. and somewhere thru the installation the pc turned off. (i came back to find this had happened)so i went to turn the system back on and it turned on for like 1 sec then nothing. so i changed psu to 3 other ones. and still nothing. so i tried the one thats in the pc im using now. but again 1 sec then off again. any ideas?