Sorry about this question but is that a F key thingey ?
Are the F keys diff on Win 10?
http://www.tomshardware.com/g00/faq/id-2569556/safe-mode-windows.html?i10c.encReferrer=aHR0cHM6Ly9kdWNrZHVja2dvLmNvbS8%3D&i10c.ua=1