My computer keeps beeping... Well, I have a neighbour who calls me to fix his computer, when in need. One day at 11:00 PM, he calls me, telling me he can't use his computer, it keeps beeping... So, I boot it up, work with it, no beeping sound... Update all his software, reboot... I hear the fabled beeping sound. Shut the computer down, open its case. Lots of dust. I've cleaned it all up, check all connections, check if everything is as it should be. Close the computer case. Boot the PC again. No beeping this time. When logging in, I pressed the Enter key on the numpad keys. Turns out, the key was stuck, courtesy of spilled coffee... Got the key unstuck, charged the guy 50€, got back home at 3:00 AM.