Is it possible to copy a collection and edit that, then use it as well as the original?, as every time i try, the first one is replaced with the new one.
Yes, it is possible. I'm not sure exactly what you're trying to do, but make sure you're copying the collection in Fear, and not just duplicating the file via copy/paste or whatever. Also make sure things like collection references, monster and unit tags are pointing to the right tags.
cheers for the help, but i'm still a little confused as i can't open the collections from the fear menu. The only way i can make a new one is to copy it and rename it which is where i get the replacement problem. if anyone could point me in the right direction it'd be much appreciated
If you hold down the shift key while launching Fear, you will get access to a bung of additional tags that Fear can't really edit, including Collections. The main reason for the shift-launch feature is so that any tag can be duplicated and assigned its own Myth II tag header.