Wont Boot

[ltfig]

I have an HP Pavilion 525w. The pc locked up one night. now the unit wont boot. when power is turned on, only the fan runs. Any and all help will be appreciated.

[123456]

More specs, please? What OS? RAM? Did you install any software or hardware before it stopped booting?

[Sylvander]

When the system worked, did you normally hear a single short beep at the end of the POST?

And don't you hear that now?

Any indication that the POST begins, and runs?
And then halts?
Any LED's blinking?

The fan that runs...
PSU fan?
How about the CPU fan?