Please Help! Computer virus preventing me from opening programs?

Somehow my computer became infected with an unknown virus. It is preventing me from running any programs including my current anti virus (spybot) or installing anything (like malwarebytes). How can I remove this nasty bug? The dialog boxes I am getting are for the scam program “spyware system pro alert” and for “pygvcj.exe”

You’ve likely gotten a Virtumundo infection.

In windows XP Home, there is no “Administor” account except in safe mode, and this account by default has no password.

However, if you cannot install malwarebytes, your last ditch effort might be reading this website:

http://www.bleepingcomputer.com/virus-removal/remove-vundo-virtumonde

However, the best bet is to competely format the system. I’ve seen several systems that were unable to be fixed and HAD to be formatted.