Ah, now I understand.. I wasn't at all clear what you were asking about hotkeys. These really aren't Windows hotkeys, but keyboard hotkeys or shortcuts specific to the keyboard. I had a Logitech keyboard with them and some of them worked and some of them didn't. What brand is the keyboard? I would go to the Manufacturer's website and see if there is any help there.
Just as an example, here is a brief discussion of Logitech keyboard hotkeys not working...
Keyboard Hotkey Issues Try the suggestion to stop and start the HID (human interface device) service. In Windows 7 you get to it by right clicking on Computer and selecting Manage and then Services and Applications.