Unfortunately, this is the wrong forum for the HTC EVO 4G, you actually want to be asking in the following forum,
However, you can try the PRL and Profile updates, most likely won't do anything. Try pulling the battery for about 30sec and then put it back in. If it continues, you may have ot do a Hard Reset and see if it does it without any apps other then stock installed. If the restarting issue is a recent occurence, can you recall which apps were installed and uninstall them?