Build me a student database

Data entry forms will allow the client to create new students, subjects, classes and grades easily

Client will be able to edit and/or delete any entry at any moment

Averages will be calculated automatically if student has all required grades (three trimesters and final-exam grade, which will be considered as a fourth trimester)

Client will be able to see her entries by printing them on a browser (this way, if a hard copy is needed, the client will be able to print by clicking the mouse)

Printed files will be sorted using student surnames

Very user-friendly interface

Can be used on multiple operating systems