Not optimum mode

[Mici]

So for no see able reason my main monitor just started saying "Not optimum mode, recommended mode 1280x1024 60hz"
This for some reason started randomly one day when I booted up Dawn of War
What will happen exactly is, if the monitor is plunged in when I boot up the comp its just displays the message, and doesn't boot up. If I plug it in half way through booting, it just dead stops and displays the message. If I only leave the cable going to my TV (2nd monitor) it boots up, and I can set the dual monitors back up, but then it starts displaying the message. And some times, very rarely, I can see it booting up on the main monitor, up to the Loading XP screen, then I get the message.
I have tried a wide variety of things down to clearing the BIOS with no luck.
Mobo is MSI K9N6PGM2 -V
Video Card is Gforce 8600 GT
Sorry for any errors in typing. Its fucking hard to see text on this TV
And thanks in advance

[Mafai]

How To Change the Screen Refresh Rate of Your Monitor in Windows XP

The default refresh rate setting is 60 Hertz (HZ); however, your monitor may support a higher setting. Check your manufacturer's documentation for information about the settings that your monitor supports.

I had this happen after a windows update once. Had to uninstall the update.

[Mici]

Thanks, but windows is not recognizing the monitor, the Nvidea Control panel is, and windows did, but not anymore

[Jotaru]

Try reinstalling monitor drivers, what do you have?

[Mici]

It is a samsung 915N
And I seem to have found a temp fix, I just pull the power cord on the monitor for about 10min and it works till I restart, fucking annoying but works for now. Thanks for the suggestions, if you have any for a permanent fix, please give them.