Re-Registering the SMTP Snap-In can be easily accomplished through the Command Prompt.
Navigate to Start -> Run. Next to the field which says Run, type in CMD and click OK. A Command Prompt window should now open.
Enter the following command:
regsvr32 "C:\Windows\system32\inetsrv\smtpsnap.dll"
Once entered, press Enter.
You should receive the following message that the job completed successfully.
