Power Supply Problems?

[nashster]

Could someone please help me figure out whats wrong with my comp. Sometimes i try to turn it on and the lights just blink and it shuts off and i have to press the power button several times before it finally starts up

 

[pengwin]

check ur wiring/

 

[Nil]

check ur wiring/

Did it always work correctly before? Did anything change? Do the fans whir?

If nothing is coming on, then I'd suspect the connections, as Pengwin suggested, or maybe even the Motherboard before I'd expect it was the PSU. However, if you can find a spare one, it's an easy enough thing to test.