So I restarted because my computer was being laggy, when it booted back up only around 3/4 of the screen is showed, and the other is black. I thought at first it might be the monitor, so I tried the monitor on my laptop and it worked perfectly. I uninstalled my 4870 video driver, and then it was back to normal. I was happy. But, then when I reinstalled its back to 3/4 of the screen. ):
did u update the video driver lately? maybe try the roll back driver option or install an older driver (im assuming you're using the latest). what size screen and what resolution are u using? also could try going into the ati control panel and accessing the resolution/monitor options from there as opposed to windows display properties. u could also just be lazy and do a system restore from a couple days ago. that usually fixes driver problems ive had without going through the laborious troubleshooting process..
elitezero you may need to use driver cleaner to delete old drivers.download driver cleaner and clean old drivers and then boot up in safe mode and use driver cleaner in safe mode.then boot again and use driver cleaner again.after that install new ati drivers/hope this helps you out.