Just updated to Beta 4. My virtual machine that I've been using constantly (WinXP SP2) will no longer boot. In Beta 3 I stopped having any kernel panics, and the VM was very steady. Now, on booting the VM, it simply locks up when it gets to the Windows welcome screen. No mouse, no keyboard, no activity in the disk/network indicators. This is on a 15" MacBook Pro, 2 Ghz, with 2 Gb RAM. I was able to successfully boot into safe mode, so I removed the parralels tools thinking that might help. It didn't. So, I booted to safe mode again, reinstalled the tools. Still no luck.