Spyware Guard 2008 is Eating My Computer

I have a Dell 2350 with Microsoft XP running on it.

A couple of weeks ago, the machine became infected with this incredible trojan/virus called Spyware Guard 2008. Apparently, I came across it when I attempted to login at MyCheckFree.com and pay a bill. My Check Free admitted the problem: check it out. Usually, I can combat these things, but I'm in week two and still struggling. It's destroying my computer.

I wonder: is this the future of computing — always fighting off infection?