So it seems that antivirus is good for something

Fattening corporate bottom lines:

Office Depot has suspended PC Health Check – its malware-scanning service – after it was accused of lying about infections to push antivirus software. 

Former Office Depot technician Shane Barnett told Seattle TV station KIRO 7 that the PC Health Check service would lie to customers that their otherwise-clean PCs were infected with malware, and that this was used to flog expensive disinfection tools. He claimed he was let go from his job because he refused to run the allegedly dodgy scanner on people's machines.

Nice.  Note to self: shop somewhere else in the future.  Not because I don't know how to deal with malware, but because I don't like doing business with crooks.