My new build is not turning on

[kas2]

I just built a new computer, and it worked perfectly for a few days. However, yesterday I left the computer on, then went to do something. When I came back, the computer was completely turned off. There weren't even any of the LED's inside the mobo, which usually stay turned on even when the PC has been shut down. NOTHING in the computer is turning on, no fans, LED's, nothing. So is there a way to isolate the problem? Is there a way to make sure my power supply is working properly? I checked to make sure all the power cables are fully plugged in,as it's been suggested that a connection could have come undone after a few days, but this does not seem to be the problem. Also, if there's a way to avoid taking out and replacing every single component one at a time, that's preferable.
My power supply is the epower Lion, http://www.epowertec.com/power_lion.html
I'm not so suspicious of this--I know it's a good psu. I have an Abit KN8 mobo, an evga 7900GT, AMD 3800x2, 2 gigs of corsair value select, a seagate baracuda 250GB HD, an NEC DVD/CD RW drive, and the CPU is cooled by a titan vanessa l-type. My generic case (http://www.geeks.com/details.asp?inv...P702-3&cat=CAS) came with a 450W PSU which I did not use.

[jayb1234]

Did you check the wall socket to see if you are getting power there, breaker might have tripped.

That PSU might have died too.

From the review on this page, it looks like it might not have been up to the specifications for handling a 7900gt and the rest of the hardware.

[kas2]

The breaker's fine, I'm thinking it might be the PSU, based on the review you gave me. I'm going to see if I can borrow a PSU from a friend to test it out. But is there a way to check if the PSU is totally dead?

[Ghost(BOO!)]

if you have a multimeter you can check the voltages

[Cricket]

Originally Posted by kas2 So is there a way to isolate the problem? Is there a way to make sure my power supply is working properly?

Try that power supply in another computer. If it doesn't start up there, it's dead.

Originally Posted by kas2 My power supply is the epower Lion, http://www.epowertec.com/power_lion.html I'm not so suspicious of this--I know it's a good psu.

Even the top rated power supply brands can have a few duds per production run. When troubleshooting computer problems it's best not to assume anything.

Cricket

[Ghost(BOO!)]

Cricket makes a good point about assuming. Also always think of the simplest answer because in most cases that's what it is

[kas2]

You guys were totally right--it was the PSU. I popped in the one that came with the case and everything is working fine. Thanks a lot for your help.