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From the Readme file:

Extracting the package
======================
1.  Click Start, select Search, then click All files and folders
2.  Type q1mie12us17.exe in the search field, then click Search.
    This will locate the file you just downloaded.
3.  Double-click the icon for q1mie12us17.exe.
4.  Click Next. Read the license agreement.
5.  Click I accept the terms in the license agreement.
6.  Click Next.
7.  Ensure that "Save files in folder" is set to
    C:\SWTOOLS\DRIVERS\MOUSE\q1mie12us17.
8.  Click Next. The necessary files will be extracted to your hard drive.
9.  Click Finish.


Before Installation
===================
If you have installed special mouse drivers or mouse software on your system,
other than the Standard PS/2 Port Mouse, Microsoft PS/2 Port Mouse, or Lenovo
PS/2 TrackPoint drivers, please uninstall them before installing the
ScrollPoint III/Pro/Optical mouse drivers.


Installing the package
======================
1.  Click Start, then click Run.
2.  Type C:\SWTOOLS\DRIVERS\MOUSE\q1mie12us17\Setup.exe, then click OK.
    The setup program will run. Follow all onscreen prompts and reboot your
    system when done.