I had the nightforce Palm version,and loaded it on an older Palm version.The battery went dead,and I lost the whole program,and it would not reload,because it is a one time deal.I called Nightforce to see if they would send me another disc,but they would not,they said it is a one time deal to prevent people from buying it and selling to other people after they load it on their's. So I lost about $80 on that little lesson.From now on,I will only use it on a PC or PPC.