Word Visual Basic 91 error and screen shakes

[stephen]

This PC has Windows 7 Pro 32 Bit
BlueChip
Microsoft Office 2010 Pro

Sometimes when Word is open a Microsoft Visual Basic error screen pops up

Run Time Error 91
Object Variable or With Block Variable not set


The above error seems to cause the screen to shake and it is not possible to click on the DEBUG button.
Also sometimes the PC freezes on this message.

But because the message is shaking and freezes up the computer I cannot click on debug.