iTunes doesn't recognize either of my iPods

I downloaded the latest update recently and since then iTunes doesn't recognize either of my two iPod touches (4th gen), even though the computer does. My iPad (1st gen) is still recognized normally. I tried uninstalling iTunes and reinstalling it several times, and that didn't work. The iPods are recognized by iTunes on other computers. The computer in question runs windows 8.1, if that makes a difference. From the look of these forums it looks like I'm not the only one who has this problem. Please help.