Here is a simple solution suitable if you are distributing programs in bulk.
Paste this code into a sub-routine that is called on start-up
What the routine does is allow uninterrupted use until 31May07.
After that date and for a month after it will allow use but a polite reminder (in frm.Licence) prompts the user to register.

'This routine checks the validity of a licence
'The first bit is the reminder if...