Why and when is a boot required

Booting from external sources does not work - problem solving

Lincoln Spector

Do you want to boot from CD, DVD or a USB drive instead of the internal hard drive? We'll tell you step-by-step how to proceed.

EnlargeStep-by-step explanation: Change the boot order in the BIOS
© iStockphoto.com/the-thor

Usually, after switching on a computer, Windows or another operating system starts from the hard disk or SSD. Sometimes it is necessary to boot from an alternative environment and not from the HDD. This is the case when you want to check the operating system for malware or start from a CD, DVD or USB drive. But in this case you might have a problem: Your PC won't boot from an external source. We show the solution!

The BIOS starts the PC

The problem is likely related to your hardware setup. This controls your computer until an operating system can take over. This "setup" is also responsible for the order in which your computer starts up. It is booted from the drive that was entered first. In most cases this will be the internal hard drive. You cannot change this setting in the operating system; you can find this function in the BIOS (basic input / output system) Of your PC. If you want to start from an external source, you have to change this here - before Windows starts.

The BIOS varies from computer to computer. In general, it can be said that you have to watch the monitor carefully when you switch on your computer. Very early in the boot process, before the Windows logo appears, you will receive the message “Press key for setup”. If you do not see this message, do some research on the Internet using the manufacturer name, the model name and the words enter as set up then how to get into the BIOS.

EnlargeSet USB CD / DVD drive as boot medium

Start BIOS

As soon as you have found out how to start the BIOS of your computer, switch on your computer and press the appropriate key before Windows starts. Timing is difficult. We recommend pressing the button shortly after the company logo appears. If Windows does start, you will have to reboot your computer and try again.

Once in the bios, go to the boot section to change the boot order. Here, too, the setting options vary. The corresponding function can be found in the boot menu or in a submenu. After you find them, change the order of the drives. To do this, select your optical drive and / or your USB storage device and save the changes made. Your computer should then start from a memory other than the hard drive.

If this doesn't work, make sure that you are not using a defective external source. You can check this on another computer.

External sources are fine, but booting is still not possible

Even though your CD / DVD drive or USB storage device is OK, does your system not boot? Try this: Switch off your computer, unplug the power cord and remove the cover of your PC. Then, disconnect the cables from the CD / DVD drive, using your other hand to grasp part of the metal frame of your computer to ground yourself. Then reconnect the drive. Depending on the configuration of your system, you can also do this with your USB hardware. Then reattach the cover and reconnect the power cord. This method is useful in the event that a small amount of corrosion has built up on the connections. By pulling out and reinserting the cables, the corrosion is eliminated. This way you can remove accumulated dust.

This article is based on a contribution from our sister publicationPCWorld.com. Translated by Steve Julius Furthmüller.