Video corruption in BIOS and screen going gray during OS boot

tas1978

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Sep 29, 2009
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18,510
The other day I decided to move all my components to a new, roomier case. After I had everything back together and verified all the power and motherboard connections were where they should be I powered it on. I was met with the video card fans revving up then slowing down repeatedly and no BIOS, no boot, no POST beeps, nothing. The only difference is the case that I was given came with an additional PATA DVD drive and a floppy drive which I had attached to the mobo.

Somewhere during my troubleshooting, I accidentally managed to unplug one of the modular PSU connections (I believe it was to two of my drives, didn't verify, but it was SATA power) and after I did that, I got a message about the CMOS configuration having been changed and to press F1 to continue. I did and the computer rebooted, but no POST beeps.

I pulled the drives and moved them around to try a different PCIe slot for the GPU, and so I could actually see the POST LED on the mobo. Still revving and slowing and no boot.

I then unplugged the IDE cables for the DVD and floppy drives. Once I did this, I started getting the MSI startup screen and it started to boot to windows, but early into the boot, the screen went gray and the GPU fans got quiet. The POST beeps were finally occurring and the POST codes looked normal. But every time it started to boot, the screen went gray.

Finally, remembering that you have to hit [DEL] to enter BIOS on MSI mobos, I got into BIOS. I started looking at the configuration and that's when the video corrupted on the lower quarter of the screen and the keyboard locked up. That's also when I smelled a slight electrical burning smell (very slight, I almost didn't notice it).

I've asked a couple of coworkers (I work for an IT firm) and two said they would bet on the mobo, and one thinks it's the GPU. I'm leaning towards the mobo, but I'm also wishing that's the case since the GPU cost 3 times what the mobo did.

Thoughts and a general consensus before I start replacing parts would be appreciated.

Windows 8.1
AMD Phenom II X4 975 Black Edition Deneb 3.6GHz Socket AM3 125W Quad-Core Desktop Processor w/ZALMAN CNPS9500A-LED 92mm 2 Ball CPU Cooler
MSI 790FX-GD70 AM3 AMD 790FX ATX AMD Motherboard
2 x CORSAIR XMS 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) (16GB total)
ASUS HD7950-DC2-3GD5 graphics card - Radeon HD 7950 - 3 GB
RAIDMAX HYBRID 2 RX-630SS 630W ATX12V V2.2/ EPS12V SLI Ready CrossFire Ready Modular Power Supply
 
Smell test. Start pulling out components, such as your video card, and see if you can determine which device smells burnt. Plus, carefully look over the offending components, and I mean, very carefully, for trouble spots. Even hard drives can have components burn on them.

No offense but I have to ask since you brought it up. You didn't plug the accidentally unplugged power cord back in while the machine was on?
 

tas1978

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Sep 29, 2009
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18,510


Thanks for the quick response! While I was tempted due to the level of tiredness while I was reassembling the machine, I did not plug it back in while running.