It isn't sleep or hibernate, because it is impossible to wake up
I have a homebuilt PC (quad core 6600 in a gigabyte P35-DS3P, running Vista32 Ultimate SP2, 4GB Ram (even if it isn't using the last .5...))
After a couple of years with no problems at all, now I'm having an intermittent problem with video, where the LCD monitor will quit getting signal feed, screen goes black. Power cycling the monitor results in a "no signal source" message that is built into the LCD. Power cycling the PC brings it right up, so it isn't a cable issue. When the screen goes black, the PC lights are all still on, and I can hear the HD spin sometimes; the DVD drive opens and closes no problem. I'm wondering if it might be a driver or windows update issue, since this only started happening in the last month or so.
I've set every Vista setting I can find to no sleep, no hibernate, high performance all the time.
I checked the bios (Award CMOS), and couldn't find any settings that looked like they might be video sleep related (and even if it were a bios setting, I'd expect it to wake back up when the mouse or keyboard provided input).
I downloaded what I think is the most recent drivers for the 7900GS (4/3/2010 driver version 184.108.40.20645), to no effect.
The only item in device manager with a yellow alert is the SM Bus controller. I used the Intel website tool to look for updates, but apparently it couldn't tell that the SM Bus controller was having problems, because it didn't come back with any recommendations.
I'm usually not in front of the PC when this happens, but a little while ago the screen went black and I grabbed the mouse fast, and it came back on. A little while later it happened again, I was a few seconds slower, and I couldn't get it to come back on.
This is really irritating because I always have to hard reboot, which means I also get the "windows did not shut down properly" alerts, etc.
Any ideas what else I can/should check? Are there any hidden logs somewhere that might give me a clue, and if so, where/how would I find them?
Well, it just happened while I was in the middle of working, no timeout. I had assumed it was a timeout issue because it always happened when the PC was idle, but now I'm thinking maybe the graphics card is overheating...
Check the temps on the 7900gs, some times when gpu overheat or have a fault that they stop sending a signal. Inspect the card's cooler for dust and to see the fan is working as it should. Besides that was it installed fresh with your os or was it an later upgrade?
The graphics card could be dying, when my 7300GT died for weeks the screen would look purpleish and at the very end (last couple of days) it would start shutting down the monitor, and sometimes the monitor wouldn't even start with the PC.
I forgot to say that I used to have three EVGA 7900gs KO and they do need attention from time to time.
I'm not sure how to check the temp of the graphics card- where would I find this info? The card was bought new (retail), and was part of the original PC build.
There was almost no dust on the top (I cleaned it off last time I had the case open). The bottom (where the fan is) does have a small amount of dust on the fan itself, but almost none on the cooling fins through which the air is drawn. I don't see an easy way to clean the fan itself, it looks like I'd have to unscrew the whole cover from the back (but since there is no dust on the fins, it probably isn't necessary.
I'm not sophisticated enough to check the capacitors or any other components, so I think that checking the running temp makes sense as a next step, if you can tell me where to look
@ mjsharma I can enter safe mode at bootup- I'll also try that to see if the problem still occurs (I'm willing to bet it will).
I don't think I initially installed aero, I think I finally installed that more recently; I know that would take more processing, so maybe I can also look at how to uninstall that and see if it helps.