How to remove all quick access file from computer in one time 

step1:

first at all press "Window+R" then open a Run dialog box and type "explorer" key word and hit enter 

or 

press "Window+E" shortcut key for open explorer

step2:

now you need to go "View Menu" and then select "Options" option it will show "change folder and search option" and click on it 

it will also open open dailog box 

step3:

in folder option dialog box select "General" tap and under "privacy" option check two option 

1).show recently used files in quick access

2).show frequently used folder in quick access

step4:

and then finaly click on "clear" button and then press "apply" and "ok" button