My father-in-law's computer (an iMac circa 2008 or thereabouts), running OS X 10.6.something, is having troubles. Apparently one of their houseguests installed some kind of antivirus thing on it and that's just making a mess out of things.

I've offered to help. Of course, that computer is in Virginia and I'm in Texas, and we're not planning a trip there any time soon. That means I need to use remote desktop to get there. The challenge, of course, is walking him through the setup, which isn't particularly friendly to non-technical users.

On a relevant Metafilter thread, there seem to be several recommendations for TeamViewer. Anybody here have experience doing this sort of thing? My #1 concern is foolproof setup when I'm not there to hold their hands.