I flashed ubuntu onto a computer and uploaded important pictures and videos to it but a power surge hit and it reverted to before i flashed it

Question

I am new to linux and tried to create a nextcloud server to hold pictures and videos for my mom but after some severe weather and power outages the server I was using reverted back to a messed up version of the install that was running before I reflashed the machine to use it as a nextcloud server. for example I installed Ubuntu Server 20.04.6 but after the surges my machine had a desktop interface without me installing one and the nextcoud server was no longer available. Any help recovering the pictures and videos would be greatly appreciated as well as any advice to keep from experiencing this problem in the future

Answer 1

It was installed onto a different partition and the old one had boot priority so a reboot form a power surge booted the old OS.