Can't Load Program

I purchased a used Gateway GP7-500 from a local university. The hard drive is clean. They provided a CD start up disc and authentication code. I attempted to load the start up program.When I am prompted to enter the code I put in the 25 number/alpha code and a window appears telling me
that the code is not valid. What to do???

 

Go back to the Univ.

 

This is from a university surplus store. There are no refunds.