Besides running up to date Anti-virus, one of the best ways to keep your computer from becoming infected (and then losing access to it while it gets re-imaged, etc.) is to keep your Operating System and applications up to date. Over the past few weeks, most major vendors have updated their software. If you run applications from any of the following vendors, you should upgrade that software as soon as you possibly can:
Mac OS/X and iOS
Adobe Reader, Flash, Shockwave, etc.
Mozilla Firefox & Thunderbird
Apple Quicktime & Safari
Below are some past, but still very applicable, Security blog articles which discuss keeping your computer software up to date:
As described in one of the articles above, browsercheck.qualys.com provides a quick one-stop check for determining your application versions and upgrading them. And, you don’t have to sign up for anything!!