I assume you've tried rebooting, and File>Go Online - tech support likely suggested those. Could also be a firewall/antivirus issue, I'd uninstall your AV software first to see if that is causing it. Have you changed anything on the computer lately?
Otherwise, yeah, uninstall & reinstall. Just to save you the trouble of potentially doing it twice, use these steps for the uninstall to make sure nothing is left behind before you reinstall:http://ftm.custhelp.com/app/answers/detail/a_id/4848