Facebook account not working

Hello, eveyone....
whenever i try to log in mine fb account it shows the message "It looks like your computer is being affected by malware. We'll help you fix the problem to keep your account secure and prevent malware from spreading to friends.
Malware is software that tries to steal personal information and causes problems when you use Facebook. Clicking or sharing links that contain spam can give your computer malware."
plz help....and it displays this message not only when i log in from mine computer but from anyone's computer.... somebody plz help