@Felthry need more info: what do you mean by "doesn't exist anymore" ? Can you turn it on in the Windows settings? (I'm assuming you use Windows)
My course of action would be to check in the device manager if the Bluetooth adapter is still there, not disabled, marked as connected
I would also look for a physical switch on your computer that might turn it on or off
If all else fails I would attempt reinstalling the adapter's drivers
@Siphonay The device manager doesn't show it at all, and it does show an "Unknown USB Device (Device Descriptor Request Failed)" that I suspect is actually the bluetooth adapter.
@Siphonay unfortunately that doesn't seem to have worked :<
@Felthry hope you manage to get it working again!