Win 7: turning indexing On and Off

Tomorrow Australian time I am getting my computer back from the shop with Win 7 and a x960/480 combo.
I have been doing some reading in the Windows 7 For Dummies and other texts, but I have found no clear description of how Indexing can be turned off (which I like to do when I am playing FSX as files go everywhere and back again as well as slowing the game), and then turn back on when I have finished.
Can anyone help me, I would be grateful.
I have been doing some reading in the Windows 7 For Dummies and other texts, but I have found no clear description of how Indexing can be turned off (which I like to do when I am playing FSX as files go everywhere and back again as well as slowing the game), and then turn back on when I have finished.
Can anyone help me, I would be grateful.