In pre-xp pc's I have always (given a separate partition and sufficient space) copied the whole OS cd to hard disc, <BR>a) to reduce use/potential loss/damge <BR>b) much faster installs <BR>c) ...
CAB or Cabinet files are compressed files that store data related to various system-based installations on a Windows PC. These can also be related to the updates to the OS as well as a driver update.