You are going to find this all a bit tricky. We will try and keep
it as simple as possible.

Drivers are small text based instructions to instruct how
your computer hardware interacts with Windows and software.

Windows very politely holds a list of your hardware devices
in a folder named Device Manager.

It is in device manager that you will find the make and model
number of your graphics card or onboard graphics chipset.

To access Device Manager in XP:
double-click on the System icon in Control Panel,
choose the Hardware tab,
and  then click Device Manager.

This link is to an image of Device Manager
http://tinyurl.com/2mvdbe

As you can see, it is composed of a tree of hardware.
Click "+" to open the sub-headings for "Display Adapters"
Exactly as in the above image.
The first thing to check is if your graphics device is functioning
correctly.
If there is a problem your graphics device will be marked with
either a yellow questionmark or exclaimation mark .

If it is "questionmarked" then post back.
If all OK -
RIGHT click on the sub-heading and select "Properties"
from the menu.
The Properties dialog should give you exact details of
your graphics device - note them precisely.
Once you have the details of make and model of your
graphics device, two things you can do:
GoTo the website of the maker of device
Click the support and/or downloads links.
Locate updates for your specific graphics device.
You must only download updates for your device,
do not make random guesses.
Download and save to a folder the updates/drivers.
Read any quides/tutorials/FAQ on the site, updating drivers
is not too tricky but you may require specific techniques for
your device.
If you have any doubts do not continue but post back.