I got the lock-out screen yesterday, with the FBI logo and a ransom demand. On rebooting, same screen came up in my user session. As a reflex, I signed on as a different user and did a system restore (not in safe mode) to 2 days back, and then ran both Avast! (up to date) and then MBAM (week old definitions) scans with network unplugged. Both came back clean.
However, researching on internet it seems that system restore isn't generally enough to get rid of it, and it could be buried deep. I did look at a site (http://botcrawl.com/...alware-removal/
) and didn't find any of the files or registry items it suggested looking for. I would appreciate help determining whether it's gone or not.