Hello there. Few days ago i bought a brand new HTC Desire 310 phone, and in few days i met a pretty interesting issue - my phone was randomly crashing (rebooting) time to time on various actions. I was even thinking about getting a new phone using my warranty card, but then I found a simple solution in about 5 minutes of actually being non-lazy, lol. The problem is the default screen lock on this phone (prolly, firmware fault). This problem is easily solved by going to
Settings -> Security -> Screen lock
and setting your Screen lock to anything but not Slide :). I've seen people with this problem around, and here is the solution. I hope HTC takes care of this issue in the next firmware update.