Shell.dll is missing on installing McAfee

Hi,
Care to help me please! I had downloaded a McAfee anti-virus and when I installed it, the following error appeared when it was about the finish the installation.

File Error
Cannot find the shell.dll.
The error that was displayed in the screen forcefully stopped the installation of McAfee.
I had referred this problem of mine to my friend and he used the System File Checking Tool to check the damaged and/or replaced files on my laptop. After his application of the system file checker that he used, he restarted the laptop but the same error had appeared. My friend had lost his hope already to fix the problem.
Please help me.
Thank you.
