happens to me all the time... just the joys of running the VIC on Vista. I usually use XP with the VIC if I am going to do extensive work in vCenter.
There is a workaround so that you can stop Aero only when the VMware Infrastructure Client is running. After you stop the VMware Infrastructure Client Aero returns:
1. Right click on the VMware Infrastructure Client icon and select properties.
2. Go to the "Compatibility mode" tab.
3. Enable "Disable visual themes" and "Disable Desktop Composition".
4. Click "OK".
Robert