checked video card it has power and runs fine.Replaced cable from monitor to the video card port.I have taken the computer to best buy they plugged it in and it worked fine.So i sent the monitor back to manafacture and it still has the same problem.

On computer startup?
If so try Safe mode (repeatively press F8 function key on Windows Startup)
Then go to Device Manager (Start-->Run-->devmgmt.msc)
Click the + sign on your Display Adaptor to expand it
Then right click on your actual Display device, and uninstall it

Go back to Normal mode (ie Restart)
Go on the web, and download the most up to date driver for your Display card (from your manufactures support page)