My computer booted to a black screen

First I need to explain I have
Sapphire Radeon HD 4350 HDMI PCIe x16 with VGA, DVI, & HDMI support
Acer P191w monitor with VGA, and DVI support

The DVI connection has been working great for several months without issue till this morning. As a simple test to see why my monitor was showing a "No Signal" Message. I found my VGA cable and connected along side the DVI cable. I had a picture that was not displaying correctly. I also had this box moving across the screen with the message "Input not supported". During this time I had no control with the monitor buttons. The Monitor setup menu would not show.

Now for the next test what will happen when I disconnect the DVI cable? The monitor blanks out for a few seconds and the picture looks fine. The monitor setup menu now works again. Now I have narrowed it down to the DVI port on the card or the DVI support for the monitor that has gone out. I suppose it could also be the cable, but the chances of the cable going out over night are very slim but possible. Now there is really only one other option for testing this further. That would be to switch monitors with another computer that has DVI support.

I am inclined to think it is my monitor that has lost DVI support. If it wasn't for the monitor setup menu, I might would suspect the graphics card. However I am under the impression that the analog signal(VGA) is a second stage that is dependent on the digital signal(DVI) within the card. If this is true as long as I have a VGA signal the DVI signal should work. It could be the cable still yet, I simply don't have another one to try as of right now.

Cliff,

One day I had the same problem, found out later that I had accidentally bumped the "Source" button on the monitor. It changed from DVI source to VGA source.

Did you check that, if your monitor has that feature?

I did check and for some reason the digital source is not working. With both cables connected the screen will black out and then reset to the VGA source.

I shut down last night and started back this morning to a no signal message.

Sorry to hear that. Do you have a DVI to VGA adapter to check the DVI port on the card?

Maybe you could borrow a DVI cable from a friend or associate to test it?

Is your monitor still under warranty?

I don't have a DVI to VGA adapter. That is an excellent suggestion by the way.

No I'm afraid not. Atleast it still works with the VGA cable. I will test it further when I have more resources to find exactly which component is at fault.

Hey Clifford, sorry I didn't spot this till now! Had any luck yet? No chance you can borrow a laptop that has an external graphics port on it to test the monitor?

If your TV supports it (most have VGA, some DVI) you can try using that just to rule out the GPU. If I had to place bets it would be the GPU because that does happen, but it shouldn't on a newer card like yours. Nibiru's suggestion of a VGA/DVI adapter was good, I guess you don't have a HDMI->DVI adapter?

No Kougar I don't have anything else to test it with at the moment. I'm gonna have to wait till I purchace or something I can use come in the door. Till then the VGA port is working nicely at the same resolution of 1440x900.

I do hope to update the thread later on the exact cause of the problem. Maybe this little write up will help others in sme way that experience the same problems as I have.

OK - My ports are working correctly today. I didn't realize this until I lost my mouse off to the side of my screen. I left both cables connected the other day. Today the computer booted with my screen spanned across both cables(connected to the same monitor).

Now this leads me to wondering why this occurred to begin with. It couldn't have been a overheat problem, I had just turned the computer on. I wouldn't think it was a glitch during bootup, I had rebooted several times in the process of figuring out why my monitor was not receiving a signal. Now that the monitor is working once more, I do hope I never find out what was the cause.

If anything further happens, I will keep you posted.