Send an email with the same account you signed up to YoWindow to
support@repkasoft.com with as many details as possible...(purchasing date...etc..)
They will be able to verify your purchase...and if validated send you the serial number...
This might take a while...lots of users misplacing or losing their serial number...
This time when you receive it...print it out and save the hard copy...
Wally©...
(Ignorance can easily be overcome...Stupidity is 4ever...)