Template merge problem with Act 2009

Hi,
we have upgraded from Act 8 -> Act 2009.
All is working fine apart from a Vista Laptop.
When he tries to Mail merger he gets an error. -

"Unable to cast COM object of type
'Microsoft.Office.Interop.Word.ApplicationClass' to interface type
'Microsoft.Office.Interop.Word._Application'. This operation failed
because the QueryInterface call on the COM component for the
interface with IID '{00020970-0000-0000-C000-000000000046}' failed due
to the following error: Library not registered. (Exception from HRESULT:
0x8002801D (TYPE_E_LIBNOTREGISTERED)).

I have spoken with Sage they say I need to uninstall the Microsoft.Office.Interop.Word Assembly from the C:\windows\assembly folder.

When I try this (remembering the OS is Vista SP1) it won't let me.
I just get a generic "Access error" (Nothing else)
There is nothing in the event log.

When we originally got the laptop it came with Micorosoft Trial of Office 2007 that we immediately removed and installed Office 2003.
So although 2007 was never used it was originally installed by Sony.

Any help would be greatly appreciated as Sage won't help as they say it is a Microsoft problem!

Kindest regards,

MikeStart Free Trial