Please help me kindly. My PC is really important to me. I upgraded my PC from windows 10 to 11 using the dev channel. Now today I restarted it and it is not booting anymore. The Windows Boot Manager from the select boot priority place in bios disappeared. I have a windows DVD with windows 10. Now what can I do? There must be a way to get my lost boot files back, there must be a CMD command or something. Can anyone help me ? I can't install windows from the DVD with windows 10 because I have GPT disk but that DVD is MBR. Bootrec rebuildbcd says the requested device could not be found.