Leak Buster saying I'm not registered

[ClarkeySR]

After buying Leak Buster a week or 2 ago it's been working fine, then all of a sudden today I tried to run it and it's telling me I need to register. After re-entering the serial number it's saying that it's not valid. Anybody know why it would do this?

[Leak Buster Support]

did you change any hardware or anything on your system?

PM me your e-mail and I can look it up and reset the license for you.