How do I start my computer if it says that it can’t find the operating system?

have you tried re-installing the operator system (put the xp disc into your computer and it will run from the disc drive.

Or you could try to restart from your backup copy of your system.

Go into the bios and select an alternate boot device such as your CD or USB drive, insert a bootable device at the location you selected (might I suggest a Ubuntu installation CD), and re-start.

Or try booting in safe mode. It’s different on various computers. It runs a stripped down version of Windows and it can allow you to go back to the last working install. You have to figure out which keys need to be used during startup, to end up in safe mode. I think it’s F8 on my old XP machine. Haven’t needed it so far on my Win 7 machine.

If you can’t go into to safe mode it sounds like the BIOS can no longer detect the hard drive. This could be because the hard drive has failed, the wire connecting the hard drive to the motherboard has come loose or the wire that connects the power to the drive is loose. It could also mean that the controller chip on the motherboard is fucked but if that was the case i doubt it would even turn on.

Go to the BIOS. If it can detect the HD it will say so in the list of drives. If it is listed here and you can’t boot from it then its probably time to get a new HD. If its not listed here then you should open the computer and check that all the wires are tightly connected (or if its a laptop that the drive is seated well in the little slot for it in the bottom).

I have had this happen to me before for one of the following reasons;

1) The drive had no OS to find.
2) The OS was corrupted and therefore unrecognizable
3) Bad boot-loader
4) Bad drive cable
5) Improperly plugged-in drive cable
6) Hard drive failure
7) Hard drive controller failure

Of those, the most common in my experience is also the simplest to fix; a drive cable worked loose.

@Lightlyseared Pretty much. After having so many issues over the last few decades, I pretty much so as you instruct almost reflexively. Usually, it isn’t there.

Agreeing with the trend, that the drive cable is probably oxidized slightly so the drive can’t be seen. It just wants to be unplugged then reseated one end at a time.

On the other hand check that the drives spins up when you apply power. You show be able to feel the drive kicking a little then with the merest of virbations when it comes up to speed.
If the drive isn’t powering up then suspect the power supply +/- 12vdc lines.
—or reseat the drive poiwer connector too why not.

Thank you that helped me so much – you all deserve a great answer!