   windows XP reinstallation
  If I format my computer and then reinstall windows XP (and office XP) will I have to reactivate it - will they let me reactivate it - or, since I activated it once that is enough? 
  Yes, i would imagine that you will need to reactivate it.  But i don''t think you will have a problem. Why don''t you axe Microsoft?   ------------------------------------------;  is there a email address for that I couldn''t find any on their site;  As long as you haven''t changed certain hardware (video card, MB, etc), then you can reactivate it without issues.Otherwise I believe you''ll need to call MS to have them do it.- Houdini ;  even if you have a different hardware, it wouldn''t be a problem. I once upgraded my mobo and reinstall windows xp and reactivate, no problem.As long as your system is not completely different it doesn''t matter. 