Recently I decided to start using Ubuntu, after trying it on a VM I decided to dual boot alongside Windows 10. Windows 10 runs on my Samsung 850 SSD, I decided to partition my HDD and run Ubuntu on there instead. After a while I decided to get another SSD purely for Ubuntu. Naively I just deleted the partition on the HDD containing Ubuntu thinking that would simply remove it altogether. Of course, Ubuntu is still listed in my Boot menu. The problem I am now having is that I am unable to boot the ISO of Ubuntu from the USB drive I am using. In the boot menu I do not get the option to boot from "UEFI USB" or anything along those lines. Instead the only relevant option is simply liste d as "Sandisk". I have tried changed the boot orders and disabling secure boot. I have used Etcher to flash the drive. I now have no idea what to do. I didn't have these issues before when I dual booted via the partitioned drive, however I used a different USB drive which is no longer in my possession.
Any help with this issue will be massivel appreciated!
many thanks