ok, 1 of 3 things is wrong with your computer.
1) the motherboard ports for the keyboard and mouse are bad (most of the time they both connect to the same part of the main board)
2) Both have been deactivated (unlikely as you'd have to do a few steps to make this happen.
3) the driver that supports the controller for the keyboard and mouse is messed up (also a possibility)
Here's what you need to do. Get a usb keyboard and mouse and plug those in and you shouldn't have any problem. In order to fix #2 and #3, you'll need a working keyboard and mouse.
Once you get this plugged in, you can look at your device manager in control panel and see if there are any ! or ? on the devices.