sorry for my bad english...
HEY GUYS, I NEED YOUR HELP PLEASE

I have a Samsung 27' LCD with HDMI input, and a pc with dvi output i have a DVI/HDMI cable and everything worked fine in the highest resolution possible for one year. I had windows vista home premium, and now installed Ultimate, and here's theproblem, in settings, i can't move the resolution to higher than 800x600 it's stuck and my pc image doesn't cover the hole lcd screen while before upgrading the OS it did.

thanks guys for you're help and i hope to hear from you soon
Stay cool' xD