Computer Will not turn on.

[Kendral77]

I put my computer together about 6 months ago, and have not had any problems with it. Yesterday morning, when I tried to turn it on, it would not power up. I didn't have any time to do anything untill last night. When I got back home, it powered on just fine. Now today it will not power on again. I opened up the case, and the mb power light is lit up. I tried swapping out power switches with one from another case of mine, but that did not help. I can't think of any thing else that I can check. Can any one help? My system is as follows

A8N 32 SLI
AMD 175 Dual Core
X1900XTX Video Card
450 Watt Antec PS

Any help would be appreaciated.

*** New Information***
In my attempts to check the problem, I have noticed a high pitched noise coming from the power supply. I'm not sure if that is normal or not, but I had never noticed this sound before. Could this indicate that my PS has taken a dive? On that note, could a bad PS still give a green light on the MB light?

 

[acole1]

PS might not be supplying enough power consistently. Have you had any crashes mid-game?

 

[EvilHomer]

I would also go with the Powwer Supply ...I was having the same exact problem and I have the same MB...I thought it was the switch on the case and replaced that but the problem still persisted...after I switched out the PSU problem was solved... ...If you have and extra PSU to swap out for now ..I would go with that..