There are some softwares which make use of the registry to remap your keys. A simple google search should give you some results.
Or if you dont want the softwares to mess with your registry, then there's a beautiful software called AutoHotkey.
Get that and write the script to replace your 'spacebar' and 'n'.
Example, you could remap your "[" key to "space" and "ctrl+[" to "[" so that you don't lose out on the default functionality of the "[" key if u need it in some cases.
Browsing through some example scripts should give you an idea of how the API for AutoHotKey is.
But again, AutoHotKey doesn't work in conjunction with ALL softwares / scenarios. For example, in an MMORPG like Ragnarok.
I do not know if the regex using softwares work in such scenarios. If they do not, then your only option is to get the keyboard repaired or replaced.