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I'm at a loss to explain this one. I have a refurbished Samsung 24" monitor that, when connected to my desktop via DVI, seems to be crashing the computer. At the very least, it seems to be crashing the display driver, which has caused 2 BSODs. It also has been frequently blanking the screen (flashing black then back on).

Unfortunately the computer itself isn't free and clear of all wrong-doing here, either. It has an ASRock A790GXH/128M motherboard and I'm using the on-board video. I've had this system about 8 months, and it has had its issues. The ATI drivers for the motherboard and video have never upgrade themselves cleanly - I always have to do a command-line uninstall and new install. Twice the on-board audio has gone out for no apparent reason - both times were fixed with driver updates. It had been working fine, but I just did a reinstall of Windows 7 and these issues started happening.

Here's the kicker - I hooked up an older LCD to the computer using VGA and it hasn't showed any of the issues! I think on the AMD790GX chipset the audio and video are on the same silicon, so it very well could be the computer. It just seems like if it were the computer it would show the same issues using VGA. This is what leads me to wonder if a defective monitor could cause these kinds of issues.

Update: I'm currently using the 9.11 ATI Catalyst drivers. I have both the SouthBridge and Display drivers installed (no Catalyst Control Panel).

Update 2: OK, the ATI display driver just crashed using a different monitor connected using VGA. I'm leaning towards bad motherboard?

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I think its the monitor and associated driver combination that are giving you trouble.

Is it possible to try booting your pc with a Ubuntu LiveCD?
You may need to get the ATI drivers for Ubuntu to get it all working... but it should help diagnose your problem.

If you get your hardware working with the Ubuntu LiveCD it proves the hardware is good. You then need to focus on the Windows 7 software.

One other way to check your hardware is to get a DVI-to-VGA adapter and connect your working VGA monitor over the DVI path. Getting the adapter may not be easy, but if it works out for you, and the VGA works on that path, you can also rule out the DVI adapter as the problem (but i think getting Ubuntu to work might be a tad easier than acquiring this adapter for the testing).

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Before reinstalling Windows 7 I had played with Ubuntu 9.10 using the Wubi installer. It installed ATI drivers for me and seemed to work fine. Besides getting it to work is there anything else I could do under Ubuntu that would help diagnose? – John Clayton Dec 15 '09 at 17:59
Also - would it be the video card driver or the monitor driver? Or both? – John Clayton Dec 15 '09 at 17:59
@John, My approach to change the OS and test with the same hardware was to rule out a hardware problem. If it works that way, all your hardware is in good shape and you just need proper/updated drivers. – nik Dec 16 '09 at 2:33
up vote 1 down vote accepted

Short Answer: No...or at least not in this case.

Long Answer: I'm an idiot. I updated the BIOS before reinstalling Windows, which wiped out the memory tweaks. I eventually ran Memtest86+ on the system and sure enough it had a ton of errors.

It turns out that running 8GB (4 x 2GB) of DDR2 1066 at 1066 MHz in AMD systems is not an easy task, even if you've got DDR2 1066 RAM, CPU, and motherboard that can support it. I tried to get it stable at 1066 MHz, but couldn't. The solution was to drop the memory speed down to 800 MHz.

Given that the on-board video takes 256MB of system memory for itself, I'm confident this was the issue. The issue has disappeared since changing the memory speed, and the memory score in Windows 7 didn't even budge!

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Are you able to check if you have a current flowing over the DVI connector? We once had a not-correctly-grounded display that, when connected to a different power plug than the computer obviously had a different phase or whatever. When we plugged the cable in, the computer would reset sometimes due to that current. After plugging both in the same wall-socket via a socket extender it worked better.

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How would I check for current over the DVI connector? The computer and monitor were both plugged into a desktop UPS. – John Clayton Dec 15 '09 at 18:22
At the time we had the problem, we had voltmeter (and oscilloscope) at hand and also could measure a voltage flowing between the grounds (metal parts for the shielding of the DVI plug) of both parts when not connected. Try this. If all you have is a very thin copper wire (like one of the many wires that you can extract from a damaged headphone cable), connect it between the two grounds without connecting the cable. It is so thin that it might get hot when connected between the two dvi shields, then you know you have a current flowing. – Thomas Dec 15 '09 at 18:39
Wait, he has said that the same power source (a desktop UPS) is used to power both the devices. The grounds should already be equal. – nik Dec 16 '09 at 2:30
@nik: You are right. The grounds should be equal. I was betting on the grounds shield of the monitor being done bad in the refurbishing process. – Thomas Dec 17 '09 at 8:30

Uninstall the monitor from the Device Manager and restart.

i recently had some issues with my 2 monitors when i changed the video card. removed them from the device manager and let windows pick them up again, that solved it.

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