I need help...soon?

Hey guys i trying to figure out how to copy pics off of videos. Like on videos off of youtube or whatever my friend told me to pause it on the picture i want and then click the "prt sc" key but my computers different than hers. hers has the "prt sc" and "sys rq" on the same on but on my computer the prt sc is on the insert key (underneath it) so i dont know what to do. can someone please help me?! thanks!!