Comp no longer boots!

[SYL\X/3K]

since u switched mobos im thinking its the PSU which is half way dead . even tho it powers up on older system doesn't necessarly mean that it WILL power up a newer system because systems these days require more voltage and Watts.
try a different PSU with 15a or more under the +12v range and see if it boots up.

 

[knightrydah]

well, it'll be a while before i can get another psu to test it out with.

 

[DEATH-INCARNATE]

I agree u should get a new PSU. i have had this problem before on a friends pc that i had to fix. Its either one of two problems. either the PSU its not supplying enough power to the mobo or there is a fault in the PSU. either way ur gona need to get a new PSU if the PSU is the problem. try a using a Friends a PSU, peferably a 400W or more PSU to double check that it is the PSU, before u go spending money on a new one.