03-08-2013 10:59 AM
Hi and Welcome to the Community!
Anytime random strange behavior or sluggishness creeps in, the first thing to do is a battery pop reboot. With power ON, remove the back cover and pull out the battery. Wait about a minute then replace the battery and cover. Power up and wait patiently through the long reboot -- ~5 minutes. See if things have returned to good operation. Like all computing devices, BB's suffer from memory leaks and such...with a hard reboot being the best cure.
Failing that, please remove and reconfigure the WiFi settings on your BB.