Right - regardless of what brand card you have there are 2 companies that make the references they are:-
NVIDIA - Drivers - Download NVIDIA Drivers
ATI - Drivers & Software
Step one -
Remove the OLD driver from add/remove programs.
Step two -
Manually navigate to C:/ and then depending what brand card you have there will be a folder called NVIDIA, (ATI is in program files then ATI) within that folder there will be one or more folders *see note* DELETE the folders that have numbers i.e. 178.66 (NVIDIA) 8.9 (ATI)
Step three -
RESTART the machine.
Step four -
Download the newest driver from the links above, install it and then REBOOT.
The new driver is installed and when a new one is released just follow the steps above.
*NOTE* some Motherboards have NVIDIA/ATI chipsets these are basically who make the Motherboard and there may be some drivers in the folders listed above DO NOT DELETE these as they are for the Ethernet/sound/USB etc just the GPU ones!