Excel Excel 2007 fails on insert userform

[MKC]

I am running Excel 2007 under Windows 10 on 2 machines. On my desktop, I can insert a userform without a problem. My laptop that is identically configured, fails when the insert userform is attempted. I have tried the simplest test - a blank spreadsheet with no code behind it and an attempt to insert userform as the first action. This fails in the same way as more complex code / userforms that I have developed previously. Any suggestions would be appreciated.