Ok here is the deal:

Last week (12-29-06) I got a message on MSN from one of my friends, that said "Is this yours? Http://somesite/myscreenname"
I clicked on it and it open, then saved some file on to my desktop with the name "screenname@hotmail.com" and it was coming up as a exe with out the exe tag at the end of the name. I closed my web browser to see what the file was and it was gone. I did a search for it and it was in the trash. so I emptied it and then scaned my computer with AVG, spybot, ad-aware, and ccleaner and found just a few things. I really didnt think that much about it till I opened my web browser again and my home page was changed. (http://www.virushelpzone.com/) so then I freaked out and tried to open Hijackthis to fix some stuff, and the program closed it self. so I went to google and tried to download the lastest one and when I did the search it closed my browser. (both Firefox and Explorer)

I'm doing another scan with everything again, right now I'm at a AVG scan and its not finding anything. I also did a search of that file again on my computer and found that it was in a prefech folder, so I got rid of it. I still cant open Hijackthis (even after renaming the file) What do I do next?!??!!?!