trojan.zlob.x.a? Man this is annoying

Hi There,

I had pop ups saying " Critical System Warning:
your system is probably infected with latest version of trojan.Zlob-X.a
Full System Optimization will greatly increase your computer's performance and prevent data loss.

click ok to download antispyware software! (Recomended)"

and also had Google coming back with you tube porn, so I used FixIEDef.zip

Can someone please help me out by telling me if that is all I have to do...? I dont seem to have the pop up or Google results now, so just want to make sure no one is watching what I am doing?

Any help greatly appreciated

Thanks,

Matt