I have read many threads on this forum and others about Win7 guests locking up Lion hosts when returning from sleep. I have tried pretty much everything I have found in posts/threads, and even opened a *paid* case for this seemingly well-known issue (as in well-known to Parallels).
The long and short of it is that, after getting nowhere with Parallels support, I have figured out the solution, which I am posting below for others in case it helps them:
1) Purchase VMware Fusion 4.
2) Install VMware Fusion 4.
3) Import your Parallels VM.
4) Test on VMware Fusion 4.
5) If successful, uninstall Parallels (note that the Parallels uninstaller does *not* uninstall everything...there are threads out there on how to address that).
Last edited: Jul 19, 2012