I would suggest you hard reset the phone. This will reprogram it to it's orginal state. You will loose any data/programs you have added to the phone. Hopefully the contacts are copied on the SIM. Use Jeyo Companion (free trial) to copy SMS and contacts from the phone with activesync if you want.
From Muchomorek "Press and hold the blue action key and switch on the phone. If it asks you to format press yes.
After you have to power it on again."
Make sure the phone is fully charged before you try a hard reset. Also be aware that a reset could fail if your firmware is botched - the phone could brick.
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