If you are able to boot into safe mode with networking, you can do what Ross suggested, or download the drivers on another computer and run them off a USB stick. Here is the thing, though. If you are totally stuck and can't boot in, and can only get into safe mode, go into Device Manager
Search -> devmgmt.msc
Navigate to Display adapters and use the drop down
What does it say? Chances are the drivers are wrong. You can try to uninstall the drivers, and reboot the system. If this still doesn't work, you need to get the right drivers on the system.
What probably happened is that Windows Update automatically installed drivers over the ones you had and messed up the display settings. This has been going on since before it was released...