in later Windows versions, if there are problems you can't easily 'fix', there is a memory bank of settings to revert to an earlier setup before the problem. This can make things run better, but, as I found recently, it can cause you to lose some things you have recently installed or made shortcuts to...etc...causing you to have to re-do some of your settings. This is a mixed blessing, obviously. If your need for space is serious, and you are running ok, then you can probably remove them..