Sounds like you are looking for an Electronic Health Record. The best site I have found is www.emrupdate.com but you can ask here too www.medicaltabletpc.com. The trick is to find one that is written to take advantage of the TPC. All EMRs will work on a TPC, if they work on XP Pro.
I would suggest that you try simply scanning your existing forms into a TPC and use them in Journal or OneNote etc. This is definitely the economical route. You might also check the AbletFactory for a beta EMR at www.abletfactory.com