There has been a lot of activity involving a Facebook hack whereby a user posts a link to a video.
The post looks like this:
"(Persons name) this is the hottest video ever! :P :P :P "
If the user clicks the link, it opens a video which will install a player in Windows and send out the same message to all your friends.
To remove it, change your Facebook password, and delete the app by going to go to Account > Application Settings and delete the HD Video Player. Also delete all the posts it made so that others don't click on it.
It seems as though this may be a vulnerability in the Facebook mobile app, which might allow a malicious interception of data.
If you click the link, you will be asked to download the “FLVDirect.exe“ file. If you do, your computer will become infected and post the message to your Facebook page.
We would also recommend that you download and install Microsoft's Windows Security Essentials, and run a scan.
As ever, we remind you to never click on links that people send in emails or post on social networking websites, especially if the language used doesn't fit the profile of the user that allegedly posted it.