My PC won't switch on. HELP!

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WedNESday
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My PC won't switch on. HELP!

Post by WedNESday » Thu May 07, 2009 1:20 pm

I was playing WOW last friday when all of a sudden the sound makes a funny kind of static/scrambling noise followed by a high pitch ringing as the screen froze and I noticed no power to my USB modem. I switched the power off and the computer back on again and it almost fully loaded windows before i was BSOD'ed (somthing about a .sys file). I switched the power off and the computer back on, but all that happens now is everything comes on (fans, HDD etc.) but there is no picture whatsoever. It just says that there is no signal. I can't hear the HDD working (i.e. doing anything with data), the motherboard has no PC speaker or POST lights, everything inside looks normal. I bought a new PSU and still have the same problem, and a GFX card from another computer didn't solve anything. The motherboard light is on and it still passes power to the fans that plug into it and the front panel too (although I can't say for certain that the fans are running at normal speed, hard to say). So I am thinking right now, is my CPU dead? What are the signs? Or could it be the motherboard or bad RAM?

P.S. YES I have googled this already... ;)

I really do need a quick answer on this one guys.

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Bregalad
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Post by Bregalad » Thu May 07, 2009 1:35 pm

Maybe you should check what's going on with the graphics card and the VGA cable ?

And it's really amazing how many PCs got down these days (mine got TWICE down). I guess curses really does exists in the real world.
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WedNESday
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Post by WedNESday » Thu May 07, 2009 1:43 pm

What do you mean exactly? Both cards that I have tried have made no difference and the cable was definately plugged in correctly. The fans were working on both cards.

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Memblers
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Post by Memblers » Thu May 07, 2009 2:43 pm

With only the CPU and memory working, generally that should be enough for it to POST.

How recent is the motherboard? Starting about 10 years ago, there were bad electrolytic capacitors going around, many people got bit by this (including me). I'd check for any bulging capacitors. http://en.wikipedia.org/wiki/Capacitor_plague

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tokumaru
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Post by tokumaru » Thu May 07, 2009 5:36 pm

I had a similar problem once and the cause was a failed memory stick. Try messing around with the memory sticks a bit. Try only one at a time, in different slots.

You could also disconnect all disc drives and remove all cards except the video one (if the MB has on-board video I'd even try with it instead of with the card).

If you can't get the basic trio (MB, CPU and RAM) to work, you have to find out which of them is faulty (since you already replaced the PSU it can't be it). Memory is easily replaceable, but if the problem is with the motherboard or the processor, the best thing you could do is buy new ones and give the thing an upgrade.

If it works, just add the discs and cards one by one to make sure it's not one of them that's causing the problem.

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Dwedit
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Post by Dwedit » Thu May 07, 2009 7:31 pm

It always helps to also check the boot order. If the hard disk isn't in the boot order, you'll get a message.

Still recommending the linux boot disk, so you can mount your Hard Disk and see if it's okay.
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tokumaru
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Post by tokumaru » Fri May 08, 2009 2:44 am

Dwedit wrote:It always helps to also check the boot order. If the hard disk isn't in the boot order, you'll get a message.

Still recommending the linux boot disk, so you can mount your Hard Disk and see if it's okay.
Pretty hard to do any of the above when there is no video output.

WedNESday
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Post by WedNESday » Fri May 08, 2009 2:57 am

Obviously, it can't post. And the whole computer is only 3 months old. I checked for any bad capacitors and there were none.

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Dwedit
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Post by Dwedit » Fri May 08, 2009 3:31 am

Normally I'd suspect the PSU (I've had two of these fail!), but you said that you already replaced it.
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Post by WedNESday » Fri May 08, 2009 7:16 am

Fixed! It was a dodgy stick of RAM. Thanks for all the help guys.

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Post by ironfist61 » Wed May 13, 2009 10:07 am

Well, that's good.
Usually if that's not the case, It's just a leaky capacitor.

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MottZilla
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Post by MottZilla » Wed May 13, 2009 2:04 pm

tokumaru is the winner! :p Congrats. I really hate it when your PC suddenly seems to just explode and refuse to work. So many things to check for failure...

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