Setting a pre-determined life for a spreadsheet

Hi, I prepare technical calculation spreadsheets for clients associated with the electricity wholesale market. Unfortunately, some clients keep the spreadsheets and I don't get paid. Is there anyway that I can program, say, a six week life into the program which would require a password to make it useable again? Is Visual Basic an option?

I don't think so. I think you would need some sort of licensing software to control it, which means paying for it.

I guess I don't mind paying for the functionality so will investigate, thanks. Just as a bit of trivia, your avatar looks like George Best, if it is my wife Helen was once his girlfriend in Manchester, UK when he owned a nightclub there in the late 60's early 70's.

Indeed it is Georgie (it is Wedding Present's album cover). That is one hell of a claim to fame, when he was at his peak and when I felt he was the best in the world ever (before and since) even though I was no United supporter. He came and played for our local club, but that was definitely in his twilight years.