I recently received a .zip file via facebook message from a friend along with the text "lol". I (incredibly stupidly) unzipped it and nothing happened.
next time upload and test files you recive at one of these places before you unzip or run it

www.virustotal.com / www.metascan-online.com / www.jotti.org if you get a message that say the file has been scanned before, click new scan button for latest result