Try rebooting and at first post screen where it counts up the memory tap the DEL key. That will get you into bios\cmos area. Do not change anything unless instructed to do so. Look for the area that says something about "Integrated" and then look for onboard display. If it is set to enable then highlight it and click the enter key. This should bring up a little box. Change the setting to disabled by checking the bottom of the screen and it should tell you how to change it. Usually it will be the page up or page down or + or - buttons. When it's set to disabled then click the F10 button to save and exit. you will be prompted again to save and exit. Click Y and the system should now reboot.
Once in windows then see if it is working and post the results in your next reply