It's unfortunate that PC security these days is more complex than it used to be. Terms like spyware and malware have become common terms associated with anti-virus software. Sadly, most applications won't clean out every malicious file.
In the last year, there has been a wave of hoax anti-virus applications that look and act like actual anti-virus programs when, in fact, they themselves are the virus. Some are rather simple to clean and mildly annoying, while others put up a good fight, disabling task manager and disallowing any software to run, claiming they're "infected."
The following are some names of the hoax anti-virus apps I've run across:
Antivirus Live (or Antivirus Live 2010)
Antivirus System Pro
System Guard (or System Guard 2009)
The following site has some really good information regarding these hoax anti-virus apps: http://www.personalantivirusremoval.com/
According to the site, there has been success using Spyware Doctor. My personal success stories have been using Malwarebytes' Anti-Malware. If the hoax anti-virus is preventing you from running other software to remove it, you may have luck running in Safe Mode. If that doesn't do the trick, a very handy tool is RKill that kills any malicious software running in the background. More information and support regarding RKill can be found here.