I reformatted a very old dell for a friend of mine, reinstalled window xp pro on it and everything worked perfect. so i shut it down and called them, they asked me to go ahead and put some anti spyware software on it. I went to restart it, everything turned on. but no mouse, keyboard or montior. So i opened it up and checked inside, the fans were still running, the power light was on, everything was connected right. First thought was maybe the video card went out, but why was the mouse and keyboard not working? Any idea's anyone?
number lock on keyboard wouldn't not turn on or any lights for that matter, i have a laser mouse hooked up and it shows a red light when picked up. but in this case no light was coming out. the VGA was connection was fine checked many times, even unhooked it and re-hooked it to a different pc. everything worked fine with the other pc. The monitor was turned on
Try resetting the BIOS. Also, my favorite PC not starting thing to check, check the capacitors on the motherboard to make sure none are puffy or leaking. Many systems I have worked on with the issue you are seeing had a bad motherboard.