Hi,
if you know the model of your PC, you can then go to the manufacturer's website and look for drivers for your model PC and load them on to a flash drive or cd and install them that way. If they don't have Windows 7 or Vista drivers, you could try getting the newest driver they have for it and run it in compatibility mode.
If that doesn't work you could put your PC model here and I can check the specs and see what driver you need.
Regards,
Eddie.