Comboboxes and Excel: Autofilling a form

A company that I recently started to work for wants to make a Excel (or MS Access) sheet that, when provided with a part number in a combo box or list, will automatically fill in three out of eight cells directly related to that information (specifically, model #, OEM, and the already selected part number.) There are five cells in the row that will need to have the data entered manually, as it is not dependent on the part number.

My experience with excel is limited to only data entry functions, and I have spent most of my free time reading the help files and such to find a way to do this. Alas, I am completely lost and must admit that I cannot do this on my own.

Anyone interested in helping may email me at any time for more information.