iPod : application launcher not working

This was the second time that my iPod behaved this way. A quick search on google revealed that it's quite a common problem. I tried hard rebooting several times to no avail. Last time when that had happen I Watson the midst of downloading an app and it hadn't completed. So my hunch was to let it complete, however this still didn't do the job. So what worked for me was to install another app. So just to repeat if you are having a problem launching apps(perhaps most of the apps, you might still be able to launch safari browser and access to app store) . The cure is to install another app.