I am able to freeze 2008 R2 on VMWare Server 2.0.1 every time I do the following:
right-click desktop->Personalize->Screen Saver->Change Power Settings->Change Plan Settings->Change Advanced Power Settings->Expand

an item such as "Display".
During the expand of an item on the Power Options Dialog, Windows 2008 R2 freezes up completely and does not recover, requiring a restart of the VM to work agian.
It also freezes elsewhere occasionally, though I have not determined how to reproduce it elsewhere.