Did you try a soft reset? Take your stylus and push it in the reset hole.
Then if it will boot up you can use a backup app to backup your contacts and whatever else you want to save. Then I suggest you go from the Start Menu to Settings/System and click on Clear Storage and follow the directions. That will hard reset your device and reset it back to the original state. Now, this will clear all contacts and apps stored in the internal memory so backup anything you want to keep before you do it.
Good Luck!
