Keyboard and mouse not working for switch on

Can you be more specific with your issue? What system do you have and OS installed?  Also, what are the keyboard and mouse models?

To receive assistance from Dell chat support, they need to verify the warranty status and ownership. Then you must troubleshoot with them.  Click the "Get Help Now" icon on the right to start a live chat session. If already out of warranty, click here for the Dell out of warranty offering.

Well Do this following basic checks

• Check USB Ports: Try different USB ports 

• Try Another Keyboard/Mouse: Rule out a hardware failure in the input devices.

• Check for Power: Make sure the keyboard/mouse lights up when connected.

Make sure as well if the mouse and keyboard are wireless make sure batteries are plugged in and readily available for it to work, make sure drivers and software is up to date and try different USB ports on the device as another community member stated. Try a alternative usb wired mouse and keyboard to see if you have the same issue. Check all basic troubleshooting steps as well.