Jason,

make sure the phone is turned off. Hold down the blue button and then turn
the phone back on. It will ask you if you would like to do a master reset.
Select yes.

This will erase everything on the phone, format the flash, and restore the
default applications. You may need to add applications that are on your CD
that came with the phone (such as task manger or system info or Lemonade) if
your phone does not have them.