I am trying to narrow down records of students by subject code and time code. I have a parameter query that prompts users to enter the values. Is there anyway that I can have a combo box instead of having users enter the data themselves? Any help would be greatly appreciated.

I presumed you have a relational tables where you have a separate tables for Students and subjects. You can use a combox control and let Access Wizard walk you though chosing the fields for your drop down items. But sometimes it's more convenient for the users if you showed all the subjects taken by a student and tab through the subjects and enter the coresponding time codes rather than switching keyboard strokes and mouse clicks.