All Treos except the 700w use the Palm OS. If you switch to a Treo, then you would want to know if your software is compatable with the version of Palm on the Treo. Your nursing program may be compatabile since it runs on the Tunsten, or it may not if the program runs on different version of the Palm OS, as said above check with the people who sold the program. The 700w is Windows Mobile 5 OS. As mentioned above BB runs on its own OS and you would need a program that runs on the BB.