Your best bet would be to go to your computer manufacturers website.
Using mine as an example:
I go to HP's website, from there I do a search for my computer model in the
search bar within the website. Your computer model should be printed
somewhere on the front of your machine. If it's not there then look on the
booklets that came with your computer (but it should be somewhere on your
PC)
So I put in zv6233nr and press search (which I can either press Enter or
click the double arrow button which performs the search).
There are 2 areas that come up with results - one is quick links - the other
is the regular search results.
The quick links displays the main links pertinent to my computer. The search
results contain everything about it.
Choose the section that says Software and Driver Downloads. (there should be
something similar for other manufacturers sites)
Next for mine they have a section to choose the operating system, so I
choose XP
Then look for the entry that says Graphics Driver or similar (might say
display driver), click the link, agree to anything that needs to be agreed
to, download the program, run the update program, and restart the computer.
You are now done with the driver update.
-Dan