When you install BackOffice 4.5 on Windows 2000, you must install Site Server 3.0 and Site Server 3.0 Service Pack 2 before you install BackOffice 4.5. When the install of Site Server 3.0 Service Pack 2 is complete, you should receive the following:

Site Server 3.0 Service Pack 2

Site Server 3.0 has been updated.
Remove any disks from the floppy disk drives
and choose OK to reboot your computer.

If you add any additional Site Server Components,
you will need to reapply the Service Pack.
Window File Protection ( WFP) will issue:
Windows File Protection

Files that are required for Windows to run properly have been
replaced by unrecognized versions. To maintain system stability,
Windows must restore the original versions of these files.

Insert your Windows 2000 Server CD-ROM now.
Insert the Windows 2000 Server CD-ROM and:

1. Press Retry. The changed files are restored. BO 4.5 will still function.

2. Restart your system.

3. Continue the installation per the Installing Microsoft BackOffice 4.5 on Windows 2000 Server white paper at http://www.microsoft.com/backofficeserver/prodinfo/installupgrade.htm.