Internet Explorer Displays Header Image Different Than FireFox Browser

I finally figured out how to change the header size and now it only looks correct in Firefox.

Internet Explorer has it cut off on the right side and the menu buttons are not in the same position covering up key components of the header image.

How do you solve this please?

Also, is there a way to make Buddypress - BP_Default theme Responsive so that it will look good on any screen size?