Please read my "Note" below my sig. This reset problem all too often results from the automatic updating feature for Market's downloaded apps.
One thing I forgot to mention is that you need to review your My Apps list periodically because new downloads will need to be "un"checked and/or sometimes an update will restore the auto-update feature. PITA, but what a difference it makes!!
I've noticed a similar behavior on mine ever since I installed Liberty 1.5, beforehand it never happened. I use Launcherpro, not ADW. Mine will freeze when I hit the power button to turn the screen back on, and I can very faintly see the lock screen showing but incredibly dim, yet I can't interact with it. Then the phone will reboot after being locked up for 30 seconds or so.I figure I might as well chime in on this.
The only time I'm getting reboots is once or twice a day after I slide to unlock. It never does a reboot otherwise. I'm running rooted (via z4root) 2.2.1 with ADWLauncher EX. A factory reset didn't change anything. Even running stock, unrooted I was getting a reboot when I slide to unlock once or twice a day. it doesn't seem like it's a full reboot either. It takes maybe 30-40 seconds to get back to a usable state, as opposed to the full minute or two when I do a manual reboot.
I've noticed a similar behavior on mine ever since I installed Liberty 1.5, beforehand it never happened. I use Launcherpro, not ADW. Mine will freeze when I hit the power button to turn the screen back on, and I can very faintly see the lock screen showing but incredibly dim, yet I can't interact with it. Then the phone will reboot after being locked up for 30 seconds or so.