Is that Windows Process Legitimate or a Virus?

Start the Windows Task Manager at any point of time and you’ll find that dozens of processes are running in your system. Some of these process names are obvious – if there’s iexplore.exe in the list, you have Internet Explorer open on your desktop – but other processes like csrss.exe or dwm.exe will often make no sense to most of us.
Is that Windows Process Legitimate or a Virus?