Should I download "hijack this" or similar?

Hi. I am pretty much a novice trying to learn on the computer, as some of you do know. I have been posting about the problem I have been having with yahoo hijacking my google searches for past two months. When this is done the address that shows in my address bar (I search from the address bar and prefer to do so) is: http://wwws.not-found-entry.com. I was using ie6. I had upgraded some time ago to ie7, hated it, back to ie6. I opted out of all things yahoo, and some time ago took all things yahoo off computer, no add ons, ect. Recently went to internet options-advanced- and disabled 'enable third party extensions'. Upgraded to ie8, tech set the search preferences, thought there'd be no more hijackings, wrong. Didn't like ie8,which was also hijacked; uninstalled back to 6. Got Firefox, chose the permanent opt out of everything add on they have, and am not having this hijack problem in Firefox. But not sure I will keep firefox, it doesn't have some things I like in ie6, may use both. So, I thought the only next step to get rid of the search hijack is to get an anti-hijack program. But Hijack this advice is that only get it if you are advanced. I am not. So would appreciate any advice as to what to do.
sheena