See if it happens in a new blank document. If it does, try starting the
application in Office safe mode by holding the Ctrl key down, keep it held
down until you get a Yes/No prompt to start the application in safe mode,
then you can let go of the Ctrl key and click Yes. Does the problem still
exist? If it doesn't there is something loading in normal mode that doesn't
in safe mode, perhaps an add-in. You could try disabling the add-ins.
Office Safe Mode
http://office.microsoft.com/en-us/help/HP101407921033.aspx
Enable/Disable add-ins in Office apps
http://office.microsoft.com/en-us/help/HA100341271033.aspx
If it still happens with all add-ins disabled, no templates or other things
loading etc... try running Office Diagnostics which replaced detect and
repair that was in 2003. Click Start, point to All Programs, point to
Microsoft Office, point to Microsoft Office Tools, and then click Microsoft
Office Diagnostics.
Office Diagnostics
http://office.microsoft.com/en-us/help/HA012340761033.aspx