The input/output board is responsible for reading or writing on any storage devices that you plug in the computer for example. It also reads information from other components of the computer. Generally, it will need replacement if the computer is unable to read/write on a flash drive that you plug in. In order to replace it, you’ll need a Phillips #00 screwdriver.
This is a guide that will help you replace the I/O board if you're having input/output issues.