I cant open any apps on my iphone 4 after upgrading the software. How do I fix it?

Try resetting your phone: hold the on/off and home buttons until you see the Apple logo (ignore the off slider that appears first), then release. If that doesn't work try downloading a free app from the app store (you can delete it later). Sometimes this will fix it.

You're welcome. Not sure about the other ones though. You might have to delete them, then reinstall them. Try it with one first to see if this will fix it. To delete an app from your phone uncheck it on the apps tab of your iTunes sync settings and sync your phone, then recheck it and sync again to restore it to your phone. Or, to do this from your phone, tap and hold the app icon until it jiggles, then tap the x to delete it. Then re-download it from the app store as a past purchase (you won't be charged a second time, see http://support.apple.com/kb/HT2519).

One more thought...if the other apps were purchased using a different Apple ID, sign in with that ID on your phone and download another free app. To do this go to Settings>Store>Apple ID, tap the ID shown, sign out, sign back in using the other ID. Then download a free app.

You're welcome.

i have this same problem and i just got my iphone 4s one day ago thanx randers4 im a iphone nooob yes this is my first one and realy dnt no wat 2 do i hope they fix this cusits realy anoying

one more thing it workes fine agian now cus i downl a free app but is this a iphone thing ore should i go back 2 the store wit this