Accessing Files

I'm new to modding, but I was wondering, how in the world do I get to some of these folders? My computer isn't displaying anything. In Rome: Total War it's fine, but in the Medieval2 folder it isn't. I am running vista on my computer.

Thanks in Advance.

You need to use the unpacker and then you can get to the files. Theres guide for it somewhere in these forums but I cant remember where.