Here’s what happened:
Grub bootloader code was written to the Master Boot Record (MBR) of the laptop hard drive. That points off to the Grub boot menu (a file called menu.lst) on the usb drive. But it’s not there so the process gives the error message 21.
Here are some solutions:
You can create a small boot partition on the laptop drive so that the boot files are always there regardless of whether the usb is connected.
You can put the boot files on a floppy disk (unaesthetic)
You can restore windows boot code to the MBR and dual boot from windows’ bootloader
Could you describe the partitions (drives) on the laptop hard disk please, including if there is any free space on it?
And also, so we can see if it’s actually possible, please boot into openSUSE and open a console/terminal window and enter these commands and copy the session dialogue back here:
I’ve edited your post to make it easier to read – hope u don’t mind.
It looks to me, in the light of your newness in Linux, that modifying the partitions on the hard drive is not the way to go – too easy to press the wrong key and make your notebook unbootable.
Instead, perhaps see whether you can use the boot-menu key on the laptop. I have a key on mine, F8, such that when I press it 1 second or so after power on at boot time, it shows a menu of which device to boot from, including my plugged-in USB drive. This approach likely would require re-installation or tweaking of the USB Linux installation. Do you have such a key to access a boot menu?