What happens when you try? My wife had something on her machine that redirected her anytime she tried to browse online. I downloaded avira (or AVG) from my computer and brought the installer over. Put it on her machine and cleared it right up. If this sounds familiar then barrow a computer and do the same thing.
run firefox portable or chrome, normally they're not as suseptable to browser hijacks and will allow you to download your anti-virus package, try avast out instead, I've found AVG to be bloated these days.