Can someone help me with this trojan i dl'ed off aim like two days ago?

okay so one day my friend IMed me this youtube link so i cliked it and it said i needed a flash update.so then i do get a flash update but by clicking the thing and so by doing so i kinda.. yeah. then it started sending a link to alllll of my friends. now a few of my friends have it too, cu z they were as stupid as me. two days ago the computer was doing fine but today it started to **** up. someone help? can i still go on AIM with that sn? can i go on it with meebo?