[Ele7eN]

just about everyone has had this problem. do a quick search of the forum and you will find the answer. you will need your MSL (master unlock code) to fix it. the easiest way to get that is to call sprint and ask them for it.

EDIT:

Here's the fix:
Most common fix for no internet!!! Thanks Rainfreak

1. Dial ##3282#
2. Click Edit and enter your MSL. (Call sprint for your MSL)
3. Tap & Highlight Active Profile.
4. Click Menu then Edit.
5. Change value to 1 then Ok, Ok again.
6. Click Yes to update the items then Ok to reset.

and/or

Try Start/Settings/System tab and click Update Profile.