Hello,
My name is Chris and, as you can see from my profile, I have 15+ years experience working with Excel/VBA and 13 years teaching them both (all levels).
The main issue with your files is that they don't consist an well organised, structural database. So, the first thing that must be done is to convert these files to such a database. The second thing that must be done is to create a user-friendly, easy to follow interface, allowing you to easily: 1. add new records, 2. edit/modify existing records, 3. search and find any "piece" of data (eg, using a patient's code, to get all her samples into a list, or selecting a samples position, to get all samples stored there). This way, there will be no need to manually edit the database files, keeping them in a standard layout, while the users could select from drop-down lists or check boxes instead of typing. Password protection can be implemented through this interface also.
Looking forward to hear from you,
Kind regards,
Chris (chriskerpini)