How the pros sniff out a malware infection

In my last column, I talked about making online shopping safer, starting with ensuring your computer isn't already infected with some devious malware. But I didn't tell readers how to confirm that their computer wasn't maliciously compromised from the start.

Let me give it a shot. First, the reality is that without extreme measures (such as comparing every file on your computer to the vendor's known, legitimate checksum), you can't have absolute assurance that your computer is malware-free. If you want that, format your computer's hard drive and reinstall everything from vendor-distributed media and content -- then disable the network card and never connect to the Internet.