Quote Originally Posted by Simon Lloyd View Post
Yes you can use OR but you have to understand that Excel security is NOT there to protect a product but merely to protect against inadvertent changes, any user above casual status or with a bit of determination will find a way round it. What i have given is a very simplistic version of protection, there is a lot more you can do but then you also need to understand VBA better first as you have to maintain it. The sheets are made xlSheetVeryHidden which means they can only be made visible by using vba and not from the worksheet menubar.
The option you describes will suit me, I suppose any protection can be beaten, but what you have described would be superior knowledge to what most of the likely users will have.
I will give it a try and if i have some problems will no doubt be back to ask for more advice.

Thanks guys, really helpful!