really important facebook question- i think someone may be messing w/ my account?!?

[Who]

so i basically logged on to facebook and it shows that i have posted stuff that i didn't
it looks like this...

my name> name of friend
(message saying something about a site giving away free i pads or a message saying if u post this about me, i'll delete my fb account- it always either one of those 2 messages, and this has happened to me like 5 times already)

i try to delete it every time, but there are so many and it keeps saying that I posted it
im worried that someone hacked in my account or that there might be a virus...

CAN SOMEONE PLEASE TELL ME HOW TO FIX THIS!?!?

ps- what does it mean when above a post it says the name of the person who posted it, then a grey triangle arrow thing, then the name of some other person
PLZ HELP!!!

[ariann]

No one is messing with you facebook: most of the time these things are viruses who posts things automatically on your wall. If you are still unsure, change your password. If the posts continue, its a virus

[ducky]

It's a common Facebook virus. Most of them have gone now but there are still a few lurking around. To prevent them happening again then don't click on a link someone sends you unless you know it is then sending you it and not a bot

[awommack]

mime two