Can't Boot: "Reboot and Select Proper Boot device" error

Screen shows error message in picture below:

This error indicates that the computer is not finding your boot drive, or not finding the boot sector of it. Here's how to check it:

• Put the control's backup stick in the external socket it it's not already plugged in.
• Turn the control off.
• Press and hold the Delete key and turn it back on. Don't release the Delete key until the CMOS setting menu comes up.
• When the CMOS page comes up, arrow over to the Boot tab, then down to Hard Disk Drives and press Enter. You should see 2 drives listed, a Sandisk or Verbatim USB drive and a generic drive, probably a Udisk.
• Press the - key to make the 2 drives swap places, then press F10 and Enter to boot from the other USB drive.

The stick that was your backup stick will now be the boot drive, and will show up as drive C:. All your tool offsets and any programs that haven't been backed up will be on your D: drive now, so you'll need to touch your tools off and maybe reload you part programs if you need one that hasn't been backed up.

Since we know that your boot drive has gotten scrambled, I don't know if any of your programs on either of your drives can be trusted, and I don't recommend copying any files off the drive that's been failing to boot.

If it will boot and run from the external drive, we'll know that the internal one is corrupted, so it will need to be replaced: part number 995-09-006, $50.

NOTE: If it won't boot from the backup stick you may need to take the front panel off the control and remove the internal usb drive. It's in the bottom USB socket below the ethernet cable. See attached VBusb.jpg. It's the tiny black plastic jelly bean with the red Sandisk logo in the bottom right corner of the computer chassis.

Meanwhile, you can run from the external stick until the internal one is replaced.