Should I worry about compatibility issues?

I am pretty sure the answer to that question is "No," but I have to be sure.

If I take my Windows 7 PC and upgrade it to Windows 8, are all my Windows 7 programs still going to work (at least in desktop mode, obviously)? My main concern is Adobe Lightroom 3. It would be a complete disaster if I upgraded my PC and Lightroom didn't work anymore.

Probably a dumb question that has been answered many times before, but I am getting the typical pre-upgrade jitters.