Step 1:
You can download any drivers for anything without having the thing plugged in, so I don't know why you are saying you can't.
nVidia Drivers
ATI drivers
Make sure that
A: You are downloading the drivers for your card.
B: They work with your Operating System.
DO NOT INSTALL THEM YET! Just download them to your desktop and leave them there until we finish Step 2.
Step 2:
Make sure the old drivers are completely gone. Do this by downloading Driver Sweeper and following the directions.
It will probably ask you to reboot after it finishes, if it doesn't, then reboot anyways.
Step 3:
On restart, Windows will automatically install stock drivers for your card, let it do that. You don't need to delete these drivers. When it finishes and tells you the device is ready to use, update the driver with the one you downloaded to your desktop.
Step 4:
Restart your PC.
Step 5:
Send me $100.00 via paypal for IT support.