Just make sure you have "System Restore" switched on.
If you get one of these things, log off/switch off immediately.
Boot windows in Safe Mode by pressing F8 before the Windows loading screen appears.
Then go to System Restore and restore your system to an earlier point in time.
This will fix everything 90+% of the time.
Sometimes this type of malware will change settings in your system registry which will hide or lock some of your folders in which case post the problem here and I (or someone else) will point you to a fix.