[tsbtx]

Power the phone off completely.

Press down the center button on the D-pad (the "enter" button) and hold the Volume Down hardkey on the side of the phone, press the power button and release the power button while still holding the "Enter" and Volume Down button. You should see a white screen that will prompt you through the rest.

I'm sure you know, but it is worth restating, it will wipe the handset. If that doesn't work, make sure to try a second card and make sure it isn't just a trashed SDcard.