CURRENT CONFIGURATION: Microsoft Outlook 2003 or 2007

OBJECTIVE: Synchronise with Salesforce

ISSUE: Salesforce icons does not appear in Microsoft Office Outlook. Re installation of Salesforce add-on doesn't help.
User can’t synchronise mails to Salesforce accounts from outlook.
I used to have Salesforce on my outlook but it has somehow mysteriously disappeared.

SOLUTION:
Microsoft Office Outlook --> Help --> Disabled Items. Enable Salesforce add-on.
Logoff, login or restart PC.