julia44:
ok not exactly what I mean. I have been to some Non zen-cart stores, where it is protected but you once you enter the main password you can login to your acct and go shopping.
I'm still not quite getting the point of that. It seems to me having a main password that gets anyone and everyone into the site (second login or not) is like not having a password at all. Someone who knows the main password can just pass it on to anyone. I guess that's just me.
You could go for an option like Momokui suggested which would do the same thing. Some hosting services also have password control available from their webmaster panel (like CPanel), although I think those may not cover the main directory.