I don't know if yours is the same problem as mine - mine was that if trying to call out the screen would go blank, and messages got stuck on loading so they wouldn't open.
I tried a factory reset and all sorts and that didn't really help. I eventually tang virgin, and they told me its sort of a known problem with the phone.
Their advice was to clear the data/cache from phone, people and messages (and I think maybe dialer? Something like that), and to delete all my text messages. At first it didn't make a difference, but after a couple of hours it seems to have and touchwood its been ok for a while now! I don't know if that would help you though. If mine stops again, they've sent me the returns stuff for them to have a look, but i'm hoping to avoid that (4 days without my phone!).
Sent from my HTC One V using Tapatalk 2