Upgrading to newer version

I've been using an older version of Repetier with my original Mendel (not Mendel Pro, not Mendel Prusa) and now I'm setting up a newer machine with the latest version, but I'm not sure of everything that is necessary.

My current setup:
Repetier v0.74
Slic3r and firmware current to the Repetier version
Windows XP

My new setup:
Repetier latest version
Windows 8.1

Do I need to change the firmware or settings to make it respond? I'm more of a mechanics than a software guy, so any help would be appreciated.

I want to extend my sincere thanks to all the kind forum members who responded to my request for help. Being able to depend on the generous assistance of those more knowledgeable than ourselves is what makes forums like this so valuable.

I will be sure to provide the same level of help to these kind members when they in turn ask for it.