Try upgrade the firmware, bring your phone to HTC service center or to the place where you bought it. This might be caused from bugs from early firmware (software) from your phone, since people keep complaining, sure HTC will make a newer firmware which is bug-free and update it to internet or to their service center.

P.s: If you still have warranty, bring it to HTC service center, it'll be free and will not broke your warranty. And don't let them have your phone by days, upgrade only need couple of hours, try to wait them, make them promise that it'll be finished by that day. Good Luck ^^