There have been a large number of reports of Word or the Office Shortcut Bar being slow to load. These have been traced to the expiry of a Verisign SSL certificate. This is linked to Word via the use of Norton Anti-Virus.

This can also affect older versions of Internet Explorer.

A fuller set of details is at Slashdot.

If you have the Office plug-in for Norton Anti-Virus enabled, it may help if you uncheck the box and disable it. You may also want to uncheck "Check for Server Certificate Revocation" in Start|Settings|Control Panel|Internet Options|Advanced|Security.