First - be very cautious about claims of spyware infections from some sites or apps. There are various almost-name-brand software apps that claim to disinfect your computer while actually infecting it or leaving trojans.

There is an interesting white paper from Symantec on Rogue Security Applications that will disable actual security settings, or they will support identity theft - while 'cleaning' your computer they will send your financial info to a third party site.

It's available here (or do a Google search for Symantec Rogue Security): http://eval.symantec.com/mktginfo/enterprise/white_papers/b-symc_report_on_rogue_security_software_WP_20016952.en-us.pdf

The bad guys are getting smarter and will hijack the Google search bar to give the appearance of a legitimate recommendation when searching for security software. They will also use 'black hat' search engine optimization to boost fake web pages into higher rankings.

If your system is infected and you're not using a reputable (C-Net, ZD labs - recommended, etc) cleaner then you might still be at risk.