They *are* the original install CD
Any changes you make to your windows configuration are likely to need something from here. But as has already been said, if you have real install media you won't need this. Many "recovery disks" point to locations in the CAB files. BTW there is a CAB file viewer utility out there. Lets you scan what's actually in them.
===
Microsoft offers them the one thing most business people will pay any price for - the ability to say "we had no choice - everyone's doing it that way." -- [link|http://z.iwethey.org/forums/render/content/show?contentid=38978|Andrew Grygus]