Need a purchase licence system for downloadable software.
User downloads demo software from website, to upgrade the software the user needs to go to the website enter their software id and email address then click 'pay button' (paypal payment). After payment is accepted simple metrics are applied to the software id and the software licence code is sent to the user by there supplied email address.
part 2: existing users can retrieve there password by entering their software id and email address, if the email address matches the one on the database then the matrics are reapplied to the code provided and the licence is sent out to the email address on file. If the email address doesnt match then it throws out an error 'email address not on file'.