This problem has stumped me before. Access is not smart enough to realize if the screen is set to a different 'zoom' than 100%. So Access is thinking that the entire form is on your screen when really it is not.
This really only applies if you have Windows 7 and maybe 8, but I have no idea about that. If you go to your display property (right click the desktop and select 'Personalize' then Display in the lower left-hand corner of the pop-up.)
If you are not set at 100% then access is missing 25-50% of your screen. access goes off of pixels, which is set in the resloution, but when using 125% Windows expands everything by 25% and that can push things right off the screen. The form does not need scroll bars to fit on your screen, just need to set your zoom to 100%.
I found this out by having a 'control bar' set to be x-250 pixels from the left (where x is total left to right pixels). However one computer could never see the control bar and it was because the screen was +125%. I have never been able to figure out how to get the current 'zoom' from Windows. I have searched through all manner of API's. I hope this is the solution you were looking for! Good Luck!!