Active Shield-McAfee Virus Scan

When I turned on my computer, I had this message from McAfee Virus Scan:

 

"Some components of Active Shield are either missing or might not have been installed properly."

 

Apparently it was installed properly at one time since this is the first time I have received

this message. 

What do this mean?   How did this happen?

Am I not being protected by McAfee Virus Scan right now?

Should I call Dell and have them direct me as to what I should do.

Or, can one of you computer wizards help me.

 

Thank you.