wnrot.exe is a process which is registered as Trojan.W32.BAGLE.
"It takes advantage of the Windows LSASS vulnerability, which creates a buffer overflow and instigates your computer to shut down. "
To see more information about this vulnerability please look
Non-system processes like wnrot.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that your registry has suffered fragmentation and accumulated invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues