Sorry in advanced - this is going to be long but i really need help.
My problem: My PC is not booting to either Ubuntu or Windows 10 and is stuck showing "Missing Operating system" and going to bios and changing boot priority between drives (i have two SSDs, one with Windows 10 and one with Ubuntu) yields the same result for both.
What i wanted to do: So this all happened in the first place because i was on windows 10 and my thesis (which involves machine learning) required some installations that were only available on Ubuntu. I decided to put Ubuntu on a separate extra SSD i had because i didn't have anymore space on my Windows OS ssd and wanted the OS's to be completely separate from each other.
What i did: to preface - i have no flash drive at home so i attempted to first create a small partition on the extra ssd and extract the Ubuntu ISO there and boot from it. This did not work so i instead tried to create a partition on my main drive with the idea of only using that partition to boot to the Ubuntu installer, while still installing everything into the second drive.
Surprisingly this worked for some reason and i was able to load into the Ubuntu installer. I made sure when installing Ubuntu, to install it on the second drive, and NOT the first drive. I can confirm this did indeed happen as when the install finished, i was able to use Ubuntu like normal, and in my files i saw my other drive with everything it had, and nothing missing (from what i could see) and i was even able to transfer a file from my first drive to my second drive that had Ubuntu.
After confirming this and feeling relieved, i continued to do my thesis work and install the dependencies for everything like normal, essentially using Ubuntu with no problems for about 2 hours. When i finished and was about to sleep, i decided to first restart my pc and boot to my windows to see if everything was fine. It wasn't. Right after it restarted i got the error "boot device not found please install an operating system on your hard disk". I thought it was only a problem with my first drive but after going into bios and changing boot priority to my second drive which has Ubuntu, that didn't work either. "Missing Operating System"
What i believe happened: After doing a bunch of research on this, i read something that said "some Linux installations will overwrite the Windows boot partition during installation, which will cause Windows to fail to start normally". While i could see this happening and it does make sense, i still have no idea why I'm not even able to boot into Ubuntu despite JUST using it and then restarting my pc and its gone?
What I'm going to do: from what i believe this fix will definitely require a flash drive, so i plan on getting one first thing when i wake up (as it's 6am here and I've spent the past 3hrs trying to fix this..) although if there is anyway to fix this without a flash drive that would be great as well. I really appreciate anyone with an idea on what to do, thank you in advanced
System specs:
Samsung 980 (non-pro) w/ Windows 10
WD Blue 2.5 SATA SSD w/ Ubuntu 22.04.2
Gigabyte B450i Aorus Pro Wifi
Ryzen 7 2700
MSI 6800XT GAMING X TRIO
