virus from anti virus 2009

i have a virus i believe is from microsoft anti virus 2009. it pops up and crashes my computer, well my internet goes off with out warning. internet as well as IM lag or wont work most of the time. I also have various pop ups from internet explorer now. i thinks it's a virus from the nicrosoft anti virus 2009. how do i fix it or get it off my computer? I'm using windows xp with media player and i use internet explorer for internet browsing. i have rebooted my computer several times and this anti virus 2009 keeps comng back up causing the computer to have pop ups. my computer is a gateway and i have had it for about 3 years now. i use charter security suite for protection but it's not helping me. i also have a pop up of something telling me i need to turn on the filtering? please help me.