Computer does not start when an external drive remains connected

[frizern]

When I try to start my computer connecting an external hardisk or pendrive from beginning then a message comes saying that,"operating system is not found,try disconnecting any drives that dos not contain an operating system." and the computer does not start.This message comes at the very beginning of the starting of computer, on the BIOS screen. Can you help me please in this regard?

 

[Cycloid Torus]

Possibly. Enter setup (BIOS) and examine devices found and boot order. You may need to refer to your manual for nuances.

Sounds like it is currently set to boot from a device with no OS and no good alternative.

 

[DelJo63]

Two devices, BOTH have a partition marked Bootable, only one actually has an OS on it.

 

[bazz2004]

Boot up into Windows before you plug in your USB stick or external hard drive. Otherwise, make changes in the bios as suggested by Cycloid. It's nothing to be concerned about.