I recently installed Parallels Desktop 4 on my Windows 7 (64-bit) machine. When I installed Ubuntu 10.10 (32-bit) on a new 'parallel' and it restarted to install updates my computer hanged and then went to BSOD. I then attempted installing Ubuntu 10.04.1 on a separate parallel and got the same result except it was right after the first restart after install. I do have VMware Workstation 7 installed but not active when I was having these issues.