Prevent Copy/Paste Ability in Excel

Is there a way to eliminate the ability to copy and paste in an Excel Worksheet?
I am working with newely created medical eval type worksheets (office 2003), and need to force Therapists to manually type in new eval data pertaining to current clients, rather than copy similar entries from other, older sheets hidden in their archives, and pasting them onto the new sheets. This practice is against medicare regs and needs to be blocked somehow.
Thank you for any help that can be afforded.