Sony Ericsson W760 hard reset
Go to Menu by pressing middle center OK button > select settings > Master reset > select Reset settings or Reset device. When You see warning message "Note: Deletes all settings and user data ..." select Cont. by pressing OK button. Phone will be restarted. Press OK to Cont.
Resetting phone. This will take a few minutes. Click OK, Memory cleared.
If nothing works: As last resort do a Sony Ericsson phone repaire with PC Suite. Use this method to hard reset AFTER INSTALLATION----> TOOLS > PHONE REPAIR