Nvidia doesn't suffer the same problem... they recently (from about 5-6 months) have added the support for mobile GPUs, in fact is possible to download from their website the drivers for GeForce Go 7000 Series and further (8000, 9000, 100, 200 etc. series - Nvidia Verde Notebook Release) also for Windows XP, so you don't have the problem with your Dell.
My GPU is an ATI Mobility HD 3650, I have tryed different ways to update drivers via Mobility Modder .NET but the latest drivers I was able to mod were the Catalyst 9.3 (more than 1 year ago!)... has anyone tryed with the latest Catalyst drivers releases? Please help me...! 😉