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PC powers on but no post

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October 26, 2010 2:51:20 PM

My PC had been acting strange for weeks. I never could figure out why. Freezing, weird graphical issues such as missing bars on top of windows and halfway loaded pictures.

Now, it will power up, fans and such running, but I get no post beep and Windows will not load. One time however I let it sit there like that powered on and several minutes later I heard post beep and Windows started up. I can't get it to do that again though.

Any help is much appreciated. Thanks for your time.

I tried putting in my Windows 7 disc but it didn't do anything.

More about : powers post

October 26, 2010 3:14:02 PM

I took everything apart. Unplugged input devices and pulled the memory. Still no post.
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October 26, 2010 3:28:17 PM

my first thought was memory. could it be power supply?

what are your full system specs?
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Related resources
October 26, 2010 3:48:28 PM

AMD Athlon 64 X2 5000+
4gb ram
geforce 8800
700watt PS
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October 26, 2010 4:00:38 PM

700W PSU? brand? model? motherboard?
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October 26, 2010 4:40:40 PM

OCZ GameXStream OCZ700GXSSLI 700W ATX12V SLI Certified CrossFire Ready Active PFC Power Supply

GIGABYTE GA-M57SLI-S4 AM2 NVIDIA nForce 570 SLI MCP ATX AMD Motherboard
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October 26, 2010 7:51:48 PM

Disconnect the video card, and try to start it up. Do you get a beep then? If yes, you've most likely got a failing PSU.
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October 28, 2010 6:48:02 PM

I took it to a guy who works on PCs and he said it might be the motherboard. But I can't find a motherboard that matched it. can anyone help me out?

GIGABYTE GA-M57SLI-S4 mobo
AMD Athlon 64 X2 5000+
4gb ram ddr2 800
geforce 8800
OCZ GameXStream OCZ700GXSSLI 700W ATX12V SLI Certified CrossFire Ready Active PFC Power Supply
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October 28, 2010 6:58:58 PM

If you want to take the chance on a used motherboard, here.
http://cgi.ebay.com/Gigabyte-Technology-GA-M57SLI-S4-At...

Any socket AM2 motherboard that accepts DDR2 800 RAM will work fine.

Did you try pulling the video card, to see if you get a beep? If you have a motherboard speaker, and it doesn't beep, then it's likely the motherboard. But if it's got a speaker and beeps, it's likely the PSU. It's worth the test.

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October 28, 2010 10:17:00 PM

i've had the exact same thing happen to my pc over the last few days.

well to be honest its been weird for a few weeks or months at least but once its booted properly its no big deal and since i rarely reboot its not been a problem.

well the other day i decided i'd change the cmos battery to avoid the pain in the butt booting and defaults loaded and such and not to mention having to reset my date and time everytime i reboot.

well i had the pc off while i went to the store and when i came back and put the battery back in it was nothing but problems.

no post to speak of just an endless retry of posting i guess.

so i ended up messing around with it for hours. took everything out put stuff back in one by one, at one point thought it was the power supply and tried another same thing. then tried another video card, same thing.

then by tiredness i hooked up the old card but forgot to hook up the dvi cable only the hdmi (i've been running two monitors for over a year) and it booted.

shut down connected the dvi and got the problem, disconnected and it booted.

so now without the dvi monitor connected i can boot and sue the pc just fine. however i still get the cmos errors on boot and it takes multiple boots before i have the dvd drive, all my hard drives and the task bar behaves right.

once its booted right i can use it no problem. been running for two days now like that without an issue but as soon as i reboot its a problem and such.

well i'm in the process of finding a replacement motherboard and/or pc upgrade.

i've talked to some techs and they've mentioned two things going/gone bad on the motherboard, one being the cmos is toast and two the southbridge is not working at all anymore which is the reason i have no dvi support.

i hope that helps some.
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October 29, 2010 8:30:27 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. We spent a lot of time on this. It should find most of the problems.

If not, continue.

I have tested the following beeps patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different.

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

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.

Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.

If no beeps:
At this point, you can sort of check the PSU. Try to borrow a known good PSU of around 550 - 600 watts. That will power just about any system with a single GPU. 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. It's possible that you can pass the POST with a defective video card. The POST routines can only check the video interface. It cannot check the internal parts of the video card.
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November 1, 2010 8:21:54 AM

thanks for the reply but i went through all the measures i could think of.

there was no beeps at all, it never even got to the bios posting screen.

i did think it was the powersupply at once time and chagned that with a spare but it didn't do anythign different. same thing with the video card.

upon speaking to a computer tech, he said that my motherboard has just gone bad, since i replaced the cmos battery if its still having the same errors as before then its bad and the other issue was a result of my southbridge goign bad and since the monitor was hooked up via dvi thats why it did that and thats why with the other hooked up via hdmi i can actually use the pc just fine (after about 10 reboots to get everything recognized) until a replacement motherboard comes, which is taking longer, can't find any i like and when i do they only have 2 memory slots and i have 4, and the ones that have four are split for ddr2 and ddr3

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