Disable all your startup apps.
As for your issue ahve you even gone to the Ubuntu Forums and asked them? They would know better off what to do. Plus by asking them maybe they can provide you with drivers or something. Since 6.06 Fiesty is their LTS right now they would probably like to know of this bug and get it fixed for Heron before it is released.
I use Gutsy on my Dell Latitude 1501 with no issues....