try going into:
home screen > press menu button at bottom > hit settings > hit applications > hit running services > hit ALL at top > scroll down to and hit Bluetooth Share > Hit Clear Cache and Hit Clear data
if that doesnt work, try first going into:
home screen > press menu button at bottom > hit settings > hit wireless & networks >scroll to bluetooth settings and try from there and to delete any possible previously paired items and to turn on bluetooth from there.
also, have you tried a hard reset?
Try this :
1) power off the phone
2) after has shut down, take off battery door cover and remove battery
3) under battery area at bottom, slide out the sim card
4) leave phone like this for 3-4 min, then slide sim back in, pop in the battery, put door back on, turn on phone
Any better?