I have 50 MAK Windows 7 licensees. I want to reformat my computer for a fresh install. How do I do this without needing to activate a 2nd time? The computer is still functioning and in fact I used it for this post
You will need to reactivate the MAK key you used on that PC once you format/reinstall Windows.
from Microsoft's Product Activation FAQ. In other words, each MAK key you have may be activated more than once. Microsoft keeps track of these at VLSC and realizes you might need to format a PC.
tl;dr Just format, install windows and activate using the same MAK key as before, you'll be fine (atleast for a couple of times).