pnkbstra.exe is a process which is usually installed with latest games like Battlefield 2142 and America's Army.
This is usually detected as malware but if removed will affect the games installed especially when online.
Non-system processes like pnkbstra.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that over time your registry suffers fragmentation and accumulates invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues