Dell 7737 Function Keys

Morning I have had a look and cant seem to find an answer, for what seems to be this simple issue. I want to turn the F1-F12 keys off from the default use, as in no matter when I am in a program, when I press f5 say then the search options comes up in Windows 8. I want them to use the default for whatever application I am using. Any ideas anyone ? Cheers Scotty