What type of an account is configured in Outlook 2010, i.e. POP 3 / IMAP / MAPI / Exchange Server?
Also do normal HTML emails go out of Outlook 2010 without issues?
If HTML emails from Outlook work fine, try to uninstall and reinstall only the Word 2010 application from the Office 2010 suit and check how it works.
http://office.microsoft.com/en-us/access-help/install-or-remove-individual-office-programs-and-components-HA010354261.aspx?CTT=1
Once you have made Word 2010 not available,
backup and delete the following registry keys.
[Start], [Run], type "regedit", [Ok]
Create a backup of the registry
Delete the following registry values:
HKEY_CURRENT_USER\Software\Microsoft\Office\8.0\Word
HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\ Word
HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\ Word
HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\ Word
HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\ Word
HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\ Word
HKEY_CURRENT_USER\Software\Microsoft\Office\ Word
HKEY_LOCAL_MACHINE\Software\Microsoft\Office\8.0\ Word
HKEY_LOCAL_MACHINE\Software\Microsoft\Office\9.0\ Word
HKEY_LOCAL_MACHINE\Software\Microsoft\Office\10.0\ Word
HKEY_LOCAL_MACHINE\Software\Microsoft\Office\11.0\ Word
HKEY_LOCAL_MACHINE\Software\Microsoft\Office\12.0\ Word
HKEY_LOCAL_MACHINE\Software\Microsoft\Office\14.0\ Word
HKEY_LOCAL_MACHINE\Software\Microsoft\Office\ Word
Close the registry editor
[Start], [Settings], [Control Panel], [Add/Remove Programs], select "Microsoft
Outlook" or "Microsoft Office", [Add/Remove], [Add/Remove Features], [Next], change
"Microsoft Outlook for Windows" to "Run from My Computer", [Update]
Restart the system and check how it works.