[TrK]

I am adding a simple note based on my experience with a Lenovo G50-80 it was submitted to me for a diagnostic check when it suddenly started continuously beeps on bootup, after it booted up it cause the laptop to be unresponsive. So i decided to take a look on that and the problem was with keyboard, in actual a key was jammed(due to some short of short-circuit) and the fact it was functioning repeatedly while in boot and normal usage causing system to be unresponsive. I suggested my friend to change the keyboard only instead of going for motherboard replacement after the replacement of keyboard it started functioning normal.

My thoughts: Every manufacture have its own beep patterns for a problem even few manufacturers doesn't imply the patterns(in most cases of desktop PCs) instead they uses the bootup process to describe the problem or may even suggest you to use motherboard diagnostic tool.