delete mw3 to install alter mw3?

im banned from mw3 and now i want to install alter mw3
i heard u need steam but can i use my banned steam acount or do i need to make a new one?
and if i need to make a new one do i need to delete mw3 map before i install alter mw3?
becouse i heard u need to download dedicated servers but it is faster if i use the dedicated server from the banned account

---------- Post added at 12:38 PM ---------- Previous post was at 11:32 AM ----------

i installed alter mw3 and it says he can't connect to the mw3 server blablabla (couse im banned)
do i need to delete a file ore something or do i need to download it all again?
or can i reinstall it with the disk?

I think you drag the Alter MW3 files into your current MW3 files which are already installed.
You can use your banned account on AlterIW.