Windows 7 VM on Fedora18 x86_64 using Virtual box.
I have Windows 7 VM was originally configured as 1 CPU, 1024 MB with Virtualbox config. My host is Fedora 18 x86_64.
Now I decide I want to add more CPU and more memory.
I can safely increase the memory (once I shutdown the VM) but any attempt to increase the number of CPU's beyond 1 causes me to first see windows contemplating the new change for a while (black screen with a slightly changing windows graphic) but then an eventual windows bluescreen with a "badconfig info" msg.
These guys http://social.technet.microsoft.com/Forums/en-US/winserverhyperv/thread/82b420b6-c0b5-4253-b3a7-d1af47b6e86c/
say this can be done - that windows eventually figures out that it's now multiprocessor. But my experience is different. Can it, in fact be done? Right now, I'm going to say no.