tldr: One day my computer (with triple boot ubuntu, xubuntu, and windows 7) was working fine. The next, no beep on POST, no BIOS splash screen and nothing ever appears on screen. Booting to ubuntu live CD shows the load progress, but the screen is scrambled when it actually starts the os (this CD has always had this behavior on this computer), but this rules out a bad video card/connection. I have no idea what’s wrong.
Read on for details…
Beep on POST – I got the beep on POST back by unplugging the computer and holding in the power button.
It seems to be booting to the OS as it is accessing the hard drive in a manner consistent with what I’m used to when everything is functioning correctly. If I attempt to enter BIOS settings, the hard drive access does not happen, seemingly verifying that I’m getting into the BIOS settings, just not seeing them.
A few days prior to this, I deleted some old files from the boot partition of one of the drives and ran boot-repair. I rebooted several times after this and everything was working as expected. I don’t think this is related, but it’s the only thing I can think of that has changed that might have caused something like this.
I have seen this many times, issue always seems to be the hard drive. unplug the hard drive and see if it passes Post. If it does, sad to say you will need to replace the drive.