If when you turn on your computer you see a message on a black screen whose full text says “Reboot and select the appropriate boot device or insert the boot media into the selected boot device and press a key” instead of the frequent Windows startup screen 7 O 8 (the error may also appear in Windows XP), then this manual should help you. (Options for the same error text – No boot device – insert boot disk and press any key, No boot device available, depending on the BIOS version). Update of 2016: boot failure and operating system not found error in Windows 10.
In reality, the appearance of this error does not necessarily indicate that the BIOS is set in the wrong boot order, may be due to hard drive errors, caused by user actions or viruses and other reasons. Let's try to consider the most probable.
A simple method that usually works
In my experience, No Boot Device errors, Reboot and Select Proper Boot Device are generally caused by more mundane things than a bad hard drive, incorrect BIOS settings or corrupt MBR registry.
The first thing to try if you encounter this error is to remove all flash drives, CD, external hard drives of your computer or laptop and try to turn it on again; startup can be successful.
If this option helped, it is a good idea to find out why boot device errors appear when drives are connected.
First, go to your computer's BIOS and look at the boot order you have set: the system hard drive must be configured as the first boot device (here's how to change boot order in BIOS, applied to a flash drive, but it is more or less the same for a hard drive). Opposite case, set correct order and save settings.
Other than that, generally in offices or old computers at home, the following causes of the error have been found: a dead battery on the motherboard and the computer unplugged, and power problems (overloads) or with the device's power supply. computer. One of the main symptoms that one of these causes is applicable to your situation is that the time and date are reset every time the computer is turned on., or they just go wrong. If this is the case, I recommend replacing the battery on your computer motherboard, take steps to ensure a stable power supply and then configure the correct boot order in BIOS.
Select proper boot device or no boot device and Windows MBR errors
Additionally, the errors described may indicate that the Windows boot loader has become corrupted. This can be generated by malicious programs (virus), power outages in the house, improper shutdown of the computer, Inexperienced user experiments with hard disk partitions (resizing, formatting), installation of additional operating systems on the computer.
I already have two step-by-step guides on this topic in., Which should help in all the above cases except the last one, which is just below.
If errors related to the boot device appeared after installing the second operating system, the above instructions may not help, and if they do, only the originally installed operating system will likely start. You can describe your situation with the operating system and the installation order in the comments, I will try to help you (generally within the 24 hours).
Other possible causes of the error
And now the less pleasant causes: problems with the boot device itself, In other words, the hard drive of the computer system. If the BIOS does not see the hard drive and you hear a strange noise (HDD), it is likely to be physically damaged and, therefore, the computer won't start. This can be caused by a falling laptop or a blow to the computer chassis, sometimes due to unstable power supply and, often, the only feasible solution is to replace the hard drive.
Note: The fact that the hard disk does not appear in the BIOS may be due to more than just its damage, I recommend checking the interface cable and the power connection. At the same time, in some cases, the hard drive may not be detected due to a computer power supply failure; if you have any suspicions about it recently, I recommend you check it (the symptoms are: the computer doesn't turn on right away , reboots when shut down and has other weird power on and off issues).
Hopefully, some of this will help you fix No boot device available or Reboot and choose proper boot device errors, If that is not the case, I asked for, I will try to answer.
