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PC doesn't turn on

  • Power Supplies
  • Components
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Last response: in Components
January 31, 2011 5:51:53 PM

PC Config :
AMD Phenom II X4 965 black edition @ 3.4 ghz
4 GB Crosair XMS DDR2
1 TB seagate+500 GB WD
1 DVD writer
ATI Radeon 5750
Mobo : Asus M4A78-EM
PSU : Crosair HX850HW

Some days ago I was playing Darksiders and my power went off but I didn't quit and my UPS ran out and computer turned off..but I didn't care but next time power came my PC wasn't turning on! I opened the case but the green light on my mobo was on.but my cpu wasn't turning on..but I saw that if I disconnect the 24pin motherboard cable and reconnect it again my cpu fan spins for a split second (well not really spins)and then stops....anyways...I tried everything but it was no use.

After some days I thought it was my PSU which was the problem.So, I bought another PSU - Cooler Master 850w.
But,here's when things start to get interesting.My new PSU didn't work either! Now..I thought my new PSU couldn't possibly be bad out of the box too! ... But then again..everything's possible right..So, I tried turning on the PC with a 500watt old PSU I had...guess what?...PC started!...but unfortunately my my old 500watt PSU had too short wires so it couldn't fit in my case.So, I had to leave it outside of my case.Now, I can't run my PC this way forever.What I wanna know is that why it is that every 850w PSU suddenly stopped working? and how to fix it?

Any suggestion will be deeply appreciated.Thanks :) 

More about : turn

a c 716 ) Power supply
January 31, 2011 8:52:10 PM

The Cooler Master is probably DOA but the Corsair got damaged because you ran the UPS down (UPS's is so you can save your work and shut down in case of power failure)
February 18, 2011 10:34:45 AM

Its unlikely that your hardware is damaged from this power outage, but i do agree with rolli that you may have damaged the PSU.

Return the recent PSU you purchased and get another.

See what happens.
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a b ) Power supply
February 18, 2011 11:08:31 AM

My advice would be send the CM back for a refund and get a decent psu.

You don't need 850w unless you are planning a monster upgrade.

Get a nice Corsair, Seasonic or XFX psu around the 550w-600w range.
December 2, 2012 7:56:21 AM

hello, i have the same problem with my asus m4a78-em. I was with UPS and when the power went off i shut down the pc. after the power comes on i turn on the pc and it works fine.But ... after an hour or two it freezed. I tried to turn it off from the front panel but i cant. The PSU works fine, i tried it on another pc. The green light on the MB lights a few second after a turn off of the psu. Any suggestions? Is the MB damaged or?