Keyboard and mouse delay and keys being held too long?

Make sure you don't have any wireless devices interfering with the signal on your wireless keyboard and mouse and make sure there receiver is near by. I know that when i tried using an old wifi adapter on my computer my wireless mouse and keyboard became super laggy... so i got rid of it and now there fine. You also may be low on battery. OR your computer CPU usage is off the charts. Check your performance monitor through the task manager and make sure the CPU isn't high. If it is, kill some processes with high cpu usage under processes.