Cannot update Windows 7 – Error message appear

I am not a techie guy, so I need help with this problem.
I am using Win 7 ultimate 32 bit on my laptop, that I recently got from my sister.
I notice that a flag like icon pops up a message that I need update but when I tried to click on the message, I receive this message that the service center can't start.
What will I need to do?

Action Center
The Windows Security Center service can't be started.
Thanks in advance.
