how to "make other forum" with same users?

[cloferba]

i dont know where write this question...but i think its a template modify..so i am here :D

i have a computers forum, which is about windows and linux..

i want to have 2 flaps up the header "Windows", and "Linux", but i dont know how to use differents indexes for each one..:

i`ll write an example:
windows index forum:
xp
vista
seven

linux index forum:
programs
news
downloads..

how can i make 2 indexes (one for linux..and one for windows) and share the same users..and the same vbulletin installation?

pd: sorry for my english if i made any mistake :down: