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PC Won't Start, No Boot or BIOS

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  • Power Supplies
  • Components
Last response: in Components
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August 16, 2010 11:41:58 AM

Hi,

Woke up this yesterday to the other half complaining that the PC wouldn't start up. Apparently it had given him a blue screen with writing on it, so he restarted but got nothing but a black screen.

Recently my power supply died, so having replaced it (with a slightly more powerfull one) its been working for over a month. The PSU fan is spinning, the CPU fan is spinning, the LED on the motherboard is lit and the lights on my keyboard light up for a short second. Apart from that nothing. Monitor is telling me its getting no signal, no hard drive activity light. I don't get the POST beep that my system usually gives off on booting up.

I havn't got any spare parts around so can't really test anything, and didn't wanna have to buy new parts unless it's absolutely necessary.

Yesterday I was leaning towards hard drive failure but after having a think it's gotta be some kind of hardware failure...

I have reseated everything which hasn't helped. I removed all the RAM and started system, motherboard beeped continuously (correct response for my motherboard with no ram).

Tried booting system with everything connected exact the hard drive, still no POST or bios access.

I have unplugged my CMOS battery and will reconnect it tonight when I go home to see if that has helped.

Any thoughts?

Computer Specs
Geil Black Dragon DDR2 4.0GB PC6400 Quad Channel Kit (4 x 1GB) 800MHz (4-4-4-12)
Intel CPU Core 2 Duo E8400 3.0GHz 1333FSB LGA775 6MB Cache
Asus P5N32-E SLI
NVIDIA GeForce 8500 GT (512 MB)
Sony DVD RW DRU-810A
Sony CD-RW CRX230EE
OCZ Stealth XStream 600W PSU
View Sonic VX924
Thermaltake Damier V5000A Black Series

More about : start boot bios

August 16, 2010 12:44:03 PM

Hello, the fact that is returned POST beeps when you took the RAM out is a good sign. Try 1 stick of RAM in different sockets then change it for a different one. If a DIMM has died this will show it as they can't really all die at the same time.

Hope that helps. Oh and by the way it can't be your HDD, if it was it would POST but not boot into windows.
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August 16, 2010 5:14:04 PM

Took out all the memory and just used one stick, PC booted but still no POST test or Windows loading. Tried each stick of RAM seperately and same, PC booted but didn't POST. Going by that the RAM is working okay....

With everything back in the case I unplugged the DVI cable from my graphics card and dug out a VGA cable and tried that, exact same, no POST.

I unplugged the graphics card, blew all the dust out of it. (not much since I did a clean last month when replacing the PSU) Plugged it back in and tried the DVI cable again, this time after about 18 seconds the PC returned a pathetic little beep from the motherboard but still no display on the screen...
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Related resources
a c 144 ) Power supply
August 16, 2010 6:45:06 PM

Work through our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-postin...
I mean work through, not just read over it.

Breadboard - that will isolate any kind of case problem.
http://www.tomshardware.com/forum/262730-31-breadboardi...

The breadboarding thread has a paragraph about how to build and test a PC in stages.

Breadboard with just motherboard, CPU & HSF, case speaker, and PSU. You do have a case speaker installed, right? If not, you really, really need one. If your case or motherboard didn't come with a system speaker, you can buy one here:
http://www.cwc-group.com/casp.html

You can turn on the PC by momentarily shorting the two pins that the case power switch goes to.

You should hear a series of long, single beeps indicating memory problems.
Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU.

If no beeps:
At this point, you can sort of check the PSU. Try to borrow a known good PSU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.
http://www.youtube.com/watch?v=5FWXgQSokF4&feature=yout...

This checks the PSU under no load conditions, so it is not completely reliable. But if
it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.

If the system beeps:
If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card. Silence or long single beeps indicate a problem with the memory.

Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST.

Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step.
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August 22, 2010 9:36:55 AM

Turned out to be the motherboard, replaced and now okay.
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!