iPad apps not working after updated to iOS5

After I updated from 4.3.5 to 5.0 on my iPad 2, the built-in apps(Safari and Calendar) work fine but other apps will not load. It simply keeps crashing and then is back to the home screen. How to fix the issue?You need to open up the App Store on your device and update all the apps you have purchased. The problem seems to be resolved. If all apps have completely updated and still crash, delete