True story. I'd been getting fed up with Firefox, in part because it was acting sluggish and flaky, so I decided to give Google's Chrome browser a try. And by "try," I mean make it my primary browser for a couple weeks.

I liked Chrome well enough, but I noticed that certain Web sites (including gadget blog Gizmodo) were very slow to load. I mean, most of the page content would appear immediately, but it would take 15-20 seconds before I could actually scroll or click a link. It got frustrating in a hurry.

On a lark, I checked Chrome's list of installed extensions, expecting to find only the two I'd installed myself. But there was a third: McAfee SiteAdvisor, which must have come preinstalled on this relatively new machine I'm using.

Can you guess the outcome? After disabling the SiteAdvisor extension, Gizmodo and other sites loaded much faster. Then I went back to Firefox and disabled it there. Same result. I won't say this is totally conclusive proof, but if you've encountered slow-loading sites and you have McAfee SiteAdvisor installed (whether you know it or not), I highly recommend giving it the boot. (Then report back here and let me know if that helps.)

This whole episode echoes something I've been saying for years, which is that security software often does more harm than good, and you should strive to use only the most minimal set of tools. (In place of SiteAdvisor, I highly recommend Web of Trust.) Indeed, just a few weeks ago I warned against overloading your PC with security software, which can gum up an otherwise healthy system.

Contributing Editor Rick Broida writes about business and consumer technology. Ask for help with your PC hassles at [email protected], or try the treasure trove of helpful folks in the PC World Community Forums. Sign up to have the Hassle-Free PC newsletter e-mailed to you each week.