BOOTMGR MISSING; Boots anyway?

[Singularity_iOS]

So I managed to pick up a virus for the first time and AVG swiftly removed it, pending a restart. I restarted to have BOOTMGR MISSING, PRESS ANY KEY TO RESTART, and then the computer boots anyway. I've never had BOOTMGR missing in the past but I have heard of it and I thought it basically meant your windows is screwed and you need to reinstall/repair. So I shit myself when I saw the message but lucky it booted anyway. It does this everytime I boot now. Is this dangerous and how do I fix it? Thanks

 

[Singularity_iOS]

Forget I said anything. I derped and forgot I had a usb with a corrupted Windows 10 installer on it. That's what it was.