What are the default settings for the monitor?
In any case...you can uninstall your current video drivers...reboot...and Windows will restore what it considers proper, using the default driver in its reserve.
At that point, you can attempt to install the correct video driver, if such was not installed on the reboot...and then adjust the onscreen resolution used.
The video drivers should be available for download from your system manufacturer's website, if you don't have the drivers CD which came with the system.
To uninstall current video drivers: Start/Run...type devmgmt.msc and hit Enter. Scroll down to Display Adapters, click plus-sign, double-click the detailed item now revealed...click Driver tab, click uninstall, click OK.
Edited by hamluis, 14 September 2011 - 04:02 PM.