Failure to boot, increased blue screen errors, random freezes and connected hardware no longer working are all symptoms of a failing motherboard. If the motherboard was just replaced or the computer is old and suddenly begins displaying these symptoms, the board may be at fault.
Changing out the motherboard is usually the last resort in computer repair, unless the computer is due to be upgraded or the motherboard was just replaced. Troubleshoot software and peripherals to confirm that the motherboard is indeed at fault.
If system instability and errors start after installing a new piece of hardware or software, uninstalling these items may correct the problem. It is also important to run a virus and malware scan to make sure that these are not causing the issues. Connected flash drives, external hard drives or CDs in the optical drive can prevent the computer from booting properly. Make sure to remove these before rebooting.
Listening for system beeps can help confirm whether the motherboard is failing as well. One beep followed by a series of three to five beeps often indicates motherboard failure. Four beeps followed by two to four beeps conveys serial port problems, which may also indicate a failing motherboard.