Unfortunately, the only way to fix this is to do a cold boot on the
phone and reset it to the factory default settings. A description on
how this works can be found at another answers page
. For the sake of saving you some time, I'll repost the answer here.
**beginning of post**
Is it just getting stuck there, or is it doing a reboot loop? If it
gets to a certain point and keeps rebooting, and if you have a memory
card inserted, try removing the memory card and turning the phone on
again. This tends to happen when a program is installed to the memory
card instead of the phone, but removing the memory card when turning on
the phone will allow it to boot all the way.
If it is getting stuck on that screen, then a hard reboot(cold boot)
will need to be done. Hopefully you have synced it with your computer
recently, because it will reset everything to factory settings and
erase everything else. If you have a memory card, be sure to remove it
before doing a hard reboot! I'm not sure if it would erase the memory
card or not, but it is best not to take the chance of leaving it in.
***WARNING: This will erase all of your files that are stored to the phone's memory!***
1. Make sure phone is off
2. Hold both softkeys (the 2 buttons below the screen with the dashes)
and turn the phone on. Be sure to keep holding the softkeys while the
phone is booting.
3 Follow the directions that will appear on the screen to complete a
hard reboot. It should ask you to press the Send key to continue or End
key to cancel.
**end of post**
Now, keep in mind that when when you are following in the instructions,
release the power button immediately after turning the phone on,
otherwise you'll have to start the process over again.