How to Change the Virtual Machine Boot Device in Virtual PC

If you’re trying to install an OS or are testing out boot disks, you might be wondering how
to change the boot device. Here’s the quick and easy technique to change it.
What we’re going to do is go into the virtual machine’s BIOS and tweak it there.

Tweaking the Boot Device

First, click on the Ctl+Alt+Del button in your virtual machine so it can reboot.

When the POS comes up (as shown in the image below), you should press the Esc key
until you bet into the BIOS menu.

Once in the BIOS menu, navigate using your left and right arrow keys until you get to
the Boot menu.

Press Enter on Boot Device Priority and you will see a menu to select your primary
booting device.

Use your + and – keys to select your primary boot device. Assuming you will use a CD,
DVD or ISO file, you should select your CDROM device as 1st Boot Device. Then press 
F10 to save and exit and you will see a screen like this:

After you confirm your changes, your virtual machine will boot and you will be able to begin
 your installation.