Computer is on but keyboard& mouse not respo

Hello,
my computer is on but the mose and keyboardis not responding this the first problem I noticed then when this happened i turned it off and on it thidn't work I heard 3 beeps then I turned it off and I unplugged everything and put them back together and the computer works fine for half day now is stoped working the power is on when I turned it on no beep the light is on but the mose and the keyboard no responding can someone help please I appreciate it thanks for your time.