Not sure if the Sensation has a removable battery or not but what I had to do with my HTC Rezound was pull the battery and SIM card and restart without the SIM. Once started and fully booted I would then have to power down the device and reinstall the SIM and power it up again. You can try the battery pull only and see if that works, and if your battery is not removable press the volume up rocker while powering on the device to simulate a battery pull.