How To Get Rid Of This Rouge Anti Virus. >: ((((?

hey, aha yeah ive had to deal with 2 of theese before, the worst was security tool, This is called antivir solution I think. but this is just annoying, well it doesnt take a genious to delete the tssd file on task manager and then blank the proxy settings on internet explorer to get back on the internet ( it some how stops me from getting on and trys to make me purchase the product ) , my anti virus system i downloaded straight after is avira, yet it still keeps on coming back??? after i shut it down or restart it I mean, does anybody no ANYWAY i can get rid of this pest. >.< Ps, i think i got it of a torrent web, not that that helps, but still.