Here's a little form to revoke all prior wills.  Don't do this unless you've also got a new will to replace the ones you revoke.  Also, don't do a new will unless you've revoked the old ones.  Why not?  Ask a damn lawyer, this is a site of free legal resources, not a free legal service.  But, just to be nice, I'll tell you why.  Its because wills written without revoking prior wills makes the new wills a codicil to the old will.  Got it?  Go see the codicil form and you'll understand a little better.