[Kotomi]

I have this popping up on my computer fell asleep last night and woke this morning with this message and even after I have rebooted the computer it only came on properly once now after I had to reset it, I got the message again and I'm stuck...

Reboot and Select proper Boot device
or Insert Boot Media in selected Boot device and press a key

rebooted this again after typing this, and seems to be working however I'm wondering what is causing this problem or an easy fix to this
so I won't keep having the issue has had it a few times today

when I rebooted earlier reason I restarted it the last time, was the computer froze, and it shouldn't be freezing considering I don't use it often and it's a lot better and newer than my laptop...
running scans on it currently