hey I hope someone can help!! I have an acer desktop, about an hour ago it slipped and fell backwards from my table. Everything seemed OK the back was a bit loose but I popped it back in, but I started up and it says 'reboot and select proper boot device' I really need my computer! Would be appreciated it someone could help
The first thing to do is to open the case (turn off the power at the mains) and check to see if there is any obvious physical damage, like a detached cable connector at the back of the hard drive.
The message you saw is not a good sign - it means that the BIOS cannot find your hard drive's boot sector, and may be indicative of physical damage to the inside of the drive - read/write heads can skip across the drive platters in an impact, and render the drive useless.
If the computer cannot boot into the hard drive, your computer is probably dead - you may need to buy a new drive, and start all over again.
Let's be optimistic - do the internal check first.