Be aware of "Security Toolbar 7.1", extremly malicious

My machine got a virus Security Toolbar 7.1 recently. After reseached web I realized that this toolbar is very dangeous -

Security Toolbar 7.1 is a dangerous toolbar and comes from very dangerous trojan zlob. It hijack your homepage and displays fake warning message to download the another fake spyware applications... If your computer is infected with Security Toolbar 7.1 hijacker then its very dangerous for your computer. The problem is it\'s very hard to remove.

Symptoms:-
User\'s homepage is changed to asecurityupdate.com or to other unfamiliar websites. Warning messages such as Virus Alert, Your Computer is Infected, Security Alert ... are popped up constantly.

After many tries failed, I reformatted and reinstalled XP. Now my machine\'s working.

Please be aware - in case you are prompted to install this toolbar, PLEASE, PLEAE reject it!!