Syst Pref can not turn Web Sharing on. How to fix it?

[Mayarosea]

Computer is Mac OS 10.6.8

In Syst Pref I want to turn Web Sharing on but instead of green, the radio button remains yellow - just can’t
Web Sharing on.

I was told most likely problem is some accidental mess-up in Apache.
I am not familiar with coding and am seeking for advise how to re-set Apache (Web Sharing) to its original settings.

Can someone please instruct me about the exact steps?

Thanks in advance!