161562 Merging 2 php scripts into 1

I have purchased 2 PHP programs that both have usernames and passwords. They both use MSQL Databases. I would think this would be hard but I want to merge the usernames and passwords to be one so that users will not have to signin twice. and also so that you go to a profile it would be just one of the profiles. If you can do a good job, I may have other jobs, to get other fuctions.