If plugging it into a different USB port doesn't work, try using a different USB cable. Your driver may also not be correctly installed; check [http://gaming.coolermaster.com/en/products/keyboards/quickfiretk/|this link] for the correct driver. If it doesn't connect to your computer but connects to another computer, it's possible that the USB port in your computer has lost connection with the computer's motherboard; if so, you'll need to open up your computer and re-attach the internal USB cable with the motherboard. Search iFixit for instructions on how to do this with your computer. You can check the [[CM Storm Quickfire Rapid Troubleshooting|troubleshooting guide]] for your device for more information.