windowssearch.exe is a process associated with Windows Desktop Search Tray from Microsoft.
It is used by the MSN Search Toolbar. This is a non-essential process.
Disabling or enabling it is down to user preference.
Non-system processes like windowssearch.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