I recently installed a 250w PSU to take over from a 450w PSU thats was not working very good and the 250w powerd it and ran well for about 2-3 weeks and i come home and its off and i went to try to turn it on it started for 3 secs then turned off, so i bought a 430 PSU and installed it today and when i push the button it did nothen, i checked my cable they where alright and i tird it one more time, did nothen, so my guess is it would be the motherboard died or something. can anyone help?