Tweaks

This document was originally a compilation of tweaks that I've gathered here and there on the internet. But two websites, their creators, administartors and especially "posters" are mainly to thank :
http://www.xp-erience.org and
http://www.tweakxp.com
Apart from that, all my apologies to the authors of these extremely useful tricks if I could not remember all of their names or aliases : having first pasted the info without thinking I'd ever distribute it, it never occured to me to keep anything more than the essential.