you can't use the keyboard and mouse for gaming

unless you get the items (eagle eye converter) where it will allow u to use keyboard and mouse for gaming

or either u buy the controller TUACT AIMON / BANNCO Fragstein for FPS game.

1 user only allocated to 1 PSN account.

so you have to create a new user for that new region account.

once u registered the user for 1 particular emails, you can only use back the same email address, otherwise it will pop out error [invalid password / email address].

it will auto downgrade, so u dun have to be worry.

1st step = back up all ur save files.
2nd step = deactivate all the PSN accounts (otherwise u lost 1 slot of the ID).
3rd step = DL the latest firm ware into thumbdrive (the naming & link are mentioned in the 1st page).
4th step = change / upg ur hdd. (make sure you back up, once u plugged out ur 40gb hdd & even though u plug it back....it will auto reformat where u will lost all ur saves files)
5th step = switch on ur ps3 and plug in the thumbdrive that contain the latest firmware ver.
6th step = restore ur save files.