You can begin with a hard reset (pull the battery for a few sec's) but I doubt if it fixes this
Next I would do a clean wipe and new install. Go here BlackBerryOS 4.x Download FAQ - UPGRADE DOWNLOADS
and pick you an OS. I use CSL as it works better on my 7290 YMMV.
Do a security wipe, then do a complete software wipe and start from scratch. Hopefully you are sync'ing with BES so you won't loose anything.