power supply? something else?

First I would like to say sorry if this has been answered, i searched, but nothing sounded like my problem. So, here goes!

My computer will sometimes not boot all the way up. The fans spin, the HDD's spin up, lights turn on, but not to the BIOS. If I turn it off and then on again (either once or a couple times) it will eventually boot up. After starting it will not shut off, even under heavy load. Also, it seems to do this most frequently when my computer hasn't been on all night/when I'm at class. Any ideas? Please say its something dumb like there are too may USB devices plugged in when I boot (I tried that BTW, nothing) Thanks for any help you can give me.

 

I think you're right.... it is probably the power supply.... 90% of power up issues are due to a bad power supply, 8% are due to a bad motherboard, and 2% are 'other'.

 

Thanks. I was afraid of that. Oh well, I suppose it happens when building your own huh In any case, I'm off to Newegg to get another one!