Your best bet is to create macros to open and close forms. Basically, you can create a menu which is simply a form with command buttons to open and close your other forms. Access has a feature called Switchboard manager which will do this for you. Assign each button on the menu to run a macr and program the macro to close the existing form before opening the new form and then have a button on the form you're opening which will close that form and open up the menu form again. This may make the database run slightly slower, however, because it has to reload each form before it displays. On a computer with more then 32MB of RAM this delay should be minimal. Mostly the older systems had problems with this.
Reports are more difficult because they don't look right if you put command buttons on them and if you simply close the report window then it won't re-open the menu window so you may want to just open the reports preview maximized and eliminate the Min Max Buttons by setting it in the form properties to None.
As far as making it so the users cannot minimize or resixze the windows, go the the form properties for each form and set each of the following as stated:
Border Style -> Thin
Min Max Buttons -> None
Thiswill open the form so that the Minimize and Maximize buttons are not there and the border cannot be resized.
Good Luck