BleepingComputer.com: Something Nasty hiding on my computer

Well for a while i've known something not quite right with my computer.
Firefox was running ALWAYS at about 50% or the computer would be running with loads of memory, like 700k but i couldnt find a culprit causing this.
Or occasionally the xp theme would flicker to ME kind of theme and then back.
I scanned with malware bytes but it didnt pick it up. Scanned with superSpyware or w.e it's called and it didnt solve the problem.
So eventually it decided to show itself and one of those fake antiviruses appeared. I updated malwarebytes and it then picked up whatever it was, and removed the antivirus.
But whatever the original problem was, it's still on my computer! Now it seems i've aquired the google redirect virus.

I've scanned with AVG too, specifically looking for rootkits and that's not picked up anything.
I've tried updating superspyware but i keep getting error messeges that it cant connect to the internet so i must 'turn off the firewall'...but i dont have one and it's not the windows default one.

Any help will be greatly appriciated.

Thankyou!

Have i posted in the wrong forums?
More info anyway: Whatever it is - it keeps installing http://www.ehow.com/how_5884337_remove-pc-_the-easy-way_.html
that fake antivirus...
As well as cutting out my internet occasionally..