2 strikes against you.
ATI is not a CAD friendly card.....period.
The openGL that that card supports is different than what SW 08 needs.
You will have to use software GL or get a new laptop.
My laptop is for occasional SW use so I cheaped out a wee bit and got a new Dell with an 8600M GT. It works very well.
If it was my primary CAD machine I would never use ANYTHING but a quadro card. Currently running 5 Quadro's and have thrown out a few old ones. I tried 3d Labs back in the early years but they was bad. FireGL is known for having driver issues but I haven't tried them for that reason (and the Quadro cards have been flawless!).