You need to find where the HiP2P program files got installed to and delete the folder HiP2P - you may be prompted for admin permission.
My HiP2P is installed at:
c:/Program Flies (x86)/HiP2P Client
I backup my HiP2P configuration changes by exporting the config setting/data. I can restore the previous saved config that had the previous HiP2P admin password. I usually save 3-5 generations.