Are you experiencing a problem? The cheque specs shouldn't need to be changed.

However make sure that Windows 7 is using the same "Measurement System" as was your XP computer. If it was "U.S." (meaning inches) before, make certain that your new computer is too (Control Panel | Region and Language | Additional Settings button, look for "Measurement System").

Then test print a cheque and let us know if there are any problems.