I think the most important thing to installing drivers, at least I have found in my experience, is to delete the previous drivers before installing the new drivers.
I advise you to reboot your computer and boot into safemode. I believe tapping F8 immediately after rebooting allows you to go into safemode.
Once in safe mode, you need to click start, right click my computer, and click on properties. Once in the properties, you need to click on the hardware tab. The click on the device drivers tab. The find your display adapater, and right click it. Then select uninstall. Afterward it will make you reboot. Reboot.
On rebooting, make sure you have the latest drivers downloaded. With the latest drivers, don't install the default drivers from XP, tell it you want to manually install your drivers, then select the location where you downloaded the latest drivers, and install.
I think that will help you install the latest drivers with complete success.
Any questions just ask.
BB