The details depend on your particular BIOS, so you'll have to figure out what you did and undo it.
Once I turned off hyperthreading and the BIOS wouldn't let me change it back. It was a bug in the BIOS, and I ended up having to update my BIOS to fix it. Updating your BIOS will fix your problem, too, partially by resetting all of your BIOS settings to the defaults. The latter might be actually what you should do: record your BIOS settings, then reset everything to factory defaults if you can find an option to do so. Then change whatever you wanted changed again.
Comments
The details depend on your particular BIOS, so you'll have to figure out what you did and undo it.
Once I turned off hyperthreading and the BIOS wouldn't let me change it back. It was a bug in the BIOS, and I ended up having to update my BIOS to fix it. Updating your BIOS will fix your problem, too, partially by resetting all of your BIOS settings to the defaults. The latter might be actually what you should do: record your BIOS settings, then reset everything to factory defaults if you can find an option to do so. Then change whatever you wanted changed again.
Reset them to default.
Thanks!