sounds like a driver issue - Download and install the latest driver for your video card, Also and missed alot - at the same time download the driver for your monitor (monitor needs a drivers 2) this will help with any resolution or mghz problems that are preventing the monitor from working correctly in windows. (if your not sure what video card you have check the manufactures product information for your brand, make, model) You can also possibly find the information under Start - all programs - accessories - system tools - system information -click the + sign next to components and then click display --- the device manager also will give you a hint on your graphic card. Worst case option, open the pc and find the name and model number for the graphic card