If you're playing from discs, my guess is that the Uplay client needs an update. While the client is closed, press ctrl-alt-del and open your Task Manager. Check the Processes tab for "UbisoftGameLauncher.exe" and end the process if it's running. Uninstall the Uplay client, then go to uplay.com and download/install a new version. Then, give that a try. Let me know if the games still don't launch.