titlephotoA study released today by security software maker Symantec raises an alarm: One in three American businesses doesn’t have basic anti-virus software installed.

Last week, the FBI and the American Bankers Association partnered on an advisory to small businesses: Dedicate a separate PC from workers’ machines, and use that machine alone for online banking.

The idea is to prevent the installation of “banking Trojans” on workers’ desktops and laptops. Workers unwittingly install the malware while Web surfing. If they also bank from that computer, the Trojan program may capture account numbers and passwords. Small businesses are at risk, the ABA warned, because they can be held accountable for financial transactions conducted surreptitiously from infected PCs.

Even then, it’s shocking that 33 percent of businesses don’t even have anti-virus software installed on their PCs. Small businesses on a budget don’t need to spend tall dollars on security. They can install the free AVG software, one of Download.com’s more popular titles. Symantec sells both individual and corporate solutions. The easy way to buy in is Norton Internet Security 2010, which lists for $70.

I got a lot of grief from New York Times readers last year for uninstalling Symantec’s software to speed up my PC. But it sure did get a lot faster. A Symantec spokesman told me that in response to customer feedback, they’ve made the latest version of the all-encompassing Norton 360 suite much less of a system hog than its predecessor.

[Image: CBC News]