I've just heard (or received a WARNING) from a friend of mine who works as an IT in a fairly large business that new windows Update is offering to install an update to Windows system (it was VISTA in his case, but it could go to XP as well) an update:
KB940510
This update, as MS puts it, will neutralize any software that may pass/escape through the Software Activation Process, but my friend warned that it also affected their legitimate software, and now they are struggling on the phone with MS.
SO be warned. It's up to you to decide what to do.