GW8.0.1 client on Windows 7

For one user account, on one machine the client freezes every time the
viewer addin is called to view any non-txt or html file i.e. all Word,
excel, pdf, jpg etc etc

It happens if the QuickViewer pane is being used, or an attachment is

Client also freezes when such attachments are added to an email

The same user account on different Windows 7 or XP machines does not have
this problem

The same machine with a different user login to a different account does not
have this problem

I have tried to blow away the local user account on the problem pc, but even
the fresh profile had the same problem

anybody seen this? or have any suggestions?

many thanks