Library not registered when early binding

[Stuart Toll]

I am trying to automate Excel 2000 from Word VBA. Late binding works ok, eg

Dim xl As Object
Set xl = CreateObject("Excel.Application")

However, I get an automation error - library not registered when I try to
use late binding (after adding a reference to the Microsoft Excel 9.0 Object
Library) and using the following code:

Dim xl As Excel.Application
Set xl = CreateObject("Excel.Application")

I have tried re-registering Excel9.olb, and reparing / reinstalling Office,
but to no avail. However, this does works ok on other PCs.

Any ideas as to how I can track down and solve this problem?
Thanks
Stuart