[jpwhre]

i just went thru this. the phone is done. it's not bricked. when you catch the moment when it will come on, flash the stock updated rom from 9-25-09. while it is doing the few second vibs, use your stylis and keep hitting soft reset til it comes on. when it starts, flash it and it will relock it too, then get it replaced. mine was doing it too, took a day of messing with it til it came back on, would stay on for a min, or 3 hours. sometimes it would just shut off and go into vib loop and then start back up again out of the blue. final straw was having to hold the soft reset button in to keep phone on, if i let go it would go into vib loop again.

just give it a whirl. i took it to corp store at first and they said it couldn't be fixed. do a backup with wmdc, or microsoft my phone while it is on again.

EDIT: i always use stock rom, and it still happened. althoug i have about 60 apps on sd card running on device. i even hard reset and put just my contacts on and it still was doing it. just try and get it going again to get it back to stock (if it's not there to begin with) and then do a claim.