Hello, Christian!
I'll do my best to answer your question.
Do the following to password protect your VI in LabVIEW 6:
Open your VI.
Select File >> VI Properties.
Select Category: Security.
Select 'Password-protected'.
Enter and verify your password.
press OK twice.
If you're using LabVIEW 5, do the following:
Open your VI.
Select Window >> Show VI Info.
Select 'Password-protected' under Locking and Password Status.
Enter and verify your password.
press OK twice.
Hope this helps.
Mark Ridgley