Internet problem

[Redbattery]

have a Dell inspiron1300.I had a trojan virus attack. I added Avast antivirus but it continues. As a result few of my ststem 32 files got corrupted. Now i have Pc-cillin antivirus. The problem is that Few of my sites like orkut, facebook, g-mail & yahoo are giving problem. I can't scrap /reply on orkut/facebook as windows don't move. My g-mail is showing in HTML vies instead of standard. My yahoo messanger is not showing any messages i send or receive. Kindly help.