If Outlook.exe is properly registered, you will find an \Outlook.exe subkey under the above key, and under the \Outlook.exe subkey you will find a string value called Path whose data references the correct path to Outlook.exe on your computer. The following figure shows the correct Outlook.exe registration on a 32-bit version of Windows.
NOTE: The path to Outlook.exe on your computer may vary from the above figure if you installed Office in a non-default location.
To resolve this problem, repair your installation of Office using the following steps:
Windows 7 or Windows Vista
Click Start, and then click Control Panel.
Then, click Programs and Features.
In the list of installed products, select your Microsoft Office product and then click Change.
Click Repair, and then click Continue.
On the Start menu, point to Settings, and then click Control Panel.
Double-click Add/Remove Programs.
In the list of currently installed programs, select your Microsoft Office product and then click Change.