I was running a Linux Mint 15 virtual machine in WorkStation 9.0.2 on a Win7X64 host.
The vm has the tools installed with file drag/drop enabled.
I was going to transfer an ssh key file by dragging it from the linux file manager to Windows Explorer.
This is a simple text file and not very big.
What happened is this:
1) The file icon moved with the mouse to the edge of the virtual machine.
2) Then the move stopped with the icon half remaining on the vm
3) Now WorkStation 9 is totally unresponsive, nothing I do seems to affect it in any way.
4) After a minute or two the laptop fan comes on whirring like mad
5) Taskmanager shows the vmware.exe process running at 12% CPU (never changing)
Total memory usage stays put at about 4.2 GB out of the 8 GB RAM available.
Now I can do absolutely nothing in WS9 to stop this, seems like the only way out is to use TaskManager and kill vmware.exe, but that will probably corrupt my virtual machine...
What the heck is causing this and how can I get out of it???
EDIT:
After about 10 minutes the vm (which uses bridged networking) caused my main machine to completely lose network access too!
So I had no choice but to use Windows task manager and kill the process. 
Network now back again so I can post this edit, plus fan back to normal speed.