I had a strange problem with my VPC today that I spent hours trying to fix. I thought it had something to do with my Wireless Intellipoint 2.0 mouse and the fact that the VM Additions was selecting the VM Addtions PS/2 mouse driver with no other options. I didn't need the bells and whistles on theVPC, but the mouse was doing some wierd visual things that were truly making me dizzy.
I tried installing the software for the mouse. The current version is Intellipoint 5.5. It won't even install on VPC. Nor would 5.2. But 5.0 did and the wierd effect went away. However, I couldn't click on anything, so that was a bust. I kept trying to go simpler - even down to v4.0,but that gave me the same no clicks problem.
After many reboots and removing and re-adding the VM Additiions, I finally noticed a mouse driver setting called “shadow” and it was selected. I unchecked it and my problem disappeared!