Exactly with it turned of a computer runs better. Also better to turn of indexing because thats a hd thrasher, or just have it on c: os i really need it. While at it turn of restore on all drives except c: os, more so if you have big files on other drives. Defragmenting don't bother also on drives with many big files, (big file say 1gb or more).
I agree snoopdos is an excellent amiga uitility. Was anything similar and as good ever made for xp ?