To see initially what is running press CTRL SHIFT ESC.
This brings up Task Manager and a bit quicker than CTRL/ALT/DEL
Many programs running in the background wil not show so to view everything
Click START Go to RUN
For example to see if Microsoft Essentials Anti Virus is working
Scroll down to Microsoft AntMalware Service. If this is listed as "started" and "automatic" it is running in the background and will work