I use mac at home, but at work I have to use Win7 PC. It makes me crazy to switch between mac/win keybard everyday, so I want to buy mac usb keyboard, but, will CMD buttons work as CTRL in windows 'out of the box'? I can use some mapping software, but it would be much better just to plug it in and use.
Command button will act as Windows button, Control as Ctrl, Option as Alt. See https://support.apple.com/en-us/HT202676 section "How Microsoft Windows Function keys are mapped to Apple keyboards".