Why do monitors shut off after Windows start?

This problem just began in the last 24 hours without any system changes or installations by me...

About 10 to 120 seconds after Windows finishes booting up my monitors go blank even though my current power management setting is "Never shut off"

The computer is still running; i can give keyboard commands to a running music program, for example, and I can HEAR that it is responding appropriately even though I can't see the interface on the screen. However no amount of clicking or other activity will wake the monitors back up.

If I reboot in Safe Mode the monitors will stay on indefintely.

If I then disable the NVIDIA (GeForce GT240) graphics driver and reboot to normal mode the monitors will stay on, albeit with rather limited generic 800x600 display capabilities.

So, this has something to do with the operation of the graphics driver (which i have now updated with no improvement).

Something is telling the graphics card to stop sending a video signal to the monitors after a certain period of time, but I don't know what to change or what to look for.

Ideas?

Hi

have you tried to change the resolution to see if that helps?

Changing the res did help diagnose this, in a round about way.

I found that the less res the card was needing to drive , the longer it would last before failing.
Thinking the card might be overheating, i looked at it and saw that the fan had stopped spinning.

I was able to spin it up manually and it ran OK for a day but gave up again so i went out and got anew card.

The old card is probably salvageable but I'll need to identify the exact fan that fits it to get a proper replacement.

Well at least your up and running what's the make and model of old graphics card.

The best test is to try the monitor on another computer or try another on yours.