Locked Screen

[cowgirl12]

I got a Coby Kyros Android Tablet 7015A off of a friend and I want to change the pattern for the lock screen but it won't let me unless I put in the pattern of what was already on it and no one knows what it was!! How can I go in and get a new pattern so that my Tablet doesn't keep shutting down & locking the screen??? Cowgirl12