Need help! PSU or M/B ?

[Maxamus]

I recently encountered a problem and its still there.
One night i turned my pc off and teh following day i tried to turn it on but nothing happened.....

So i tried the normal procedure, clearing CSMOS etc

Now i dont know if its the mobo or the psu that is defected.
Is there anyway i can test the PSU to see if it is working?
Can it be turned on some how independently of the mobo..?

One of the two is messed up and i need to know which to replace but i dont know which is defected........any ideas?

[Kynoch]

When you try to turn the computer on do any of the attached fans on the mainboard or case fans turn on?
If they dont, have you checked that the switch connector on the mainboard is correctly attached.
If it is then i would recommend disconnecting all the deviced which are hooked upto the psu including the mainboard and then have a look at this guide http://modtown.co.uk/mt/article2.php?id=psumod which will let you try and turn on the psu without the mainboard connected, if it turns on then you know the psu works, and if it doesnt then you know the psu doesnt work.

[dangerous_dom]

Don't forget - Asuming the the PSU is actively cooled - (i.e with a fan) and the PSU fan is not spinning, check the fuse first!