Windows 7 shortcut ons died...?

my f1 through f12 ons used to have shortcut uses, like f11 was mute... and such. But my computer recently caught a kamikaze virus and completely died. My friend was able to reboot it, but when she did, a couple things were... different. The shortcut ons have somehow reverted back to being 'normal' f1 through f12 ons.How do I switch it back to shortcuts?