what should work is to provide a driver for your monitor. It W7 set it up as a generic or the wrong device, it may limit your options. I was fortunate in that W7 recognized mine by name and model.
I have an HP dv5135 notebook that I dual-booted with XP and Win 7 beta. I used Vista drivers on Win 7, and was able to gain use of all of my hardware. The video driver worked correctly and I gained the full 1280x800 resolution. Unfortunately, the same video driver is not working on Win 7 RC, so I'm stuck in a 1024x768 resolution on a widescreen monitor.
Is anyone familiar with a driver that will work on Win 7 for an ATI Radeon Xpress 200 Series video adapter? I have tried the XP and Vista versions directly from HP's website, along with the same from ATI/AMD's website.