iPhone freezes and randomly wakes up from sleep 3G

I did a standard PC sync to iTunes Friday 12/11 with no software update. Ever since, my iPhone 3G applications (safari/mail/messages) will freeze then close completely. The phone also restarts itself without warning, and when its connected to a charger (either wall or PC) it will wake up from sleep with the clock showing the wrong time, chime like youve just connected the charger then after a few seconds it will chime again and the clock returns to normal and the phone goes back to sleep. Ive tried doing a restore from backup using iTunes. Do I need to do a restore as if its a new iPhone? Does anyone have any suggestions?
3G Windows Vista