a "drivers" disk that came w/ your laptop. It should contain the mouse drivers you mention.

Some laptops etc have a separate partition on the HD (usually called D: ..) which contains a full set of OEM system files.
This is used to re-install or reformat the system back to factory original (including all the OE junk trail stuff like Norton A/V etc etc).
The idea was for new user to Burn their own Restore CD's by copying those D: drive files.

Likely if you call up "Device Manager" function, it will look in D: to find those drivers and re-install them for you. Good Luck! Happy