The drivers for many of the older ATI mobility radeon cards are no longer being updated on the Dell site.
As these drivers are only available from Dell, it is impossible to update the drivers to the latest ATI catalyst version.
Well not completely impossible. The solution is to use modded drivers:
Now you will have the latest ATI catalyst drivers. The latest drivers fix a problem in Vista where waking from sleep resets the laptop.
For those with blu-ray disc, Modding is NOT RECOMMENDED! It will break blu-ray playback using non-WHQL drivers!
Just install via the device manager and keep the WHQL signature in tact so blu-ray playback won't be disabled!