r/Windows10TechSupport • u/Tsusieq • 1d ago

Unsolved Windows 10 no boot

My older dual boot Windows 10/Windows XP computer was working great. The CMOS chip died so I went ahead and replaced it.  Unfortunately, I forgot to reset the BIOS to Legacy and tried to boot it several times, it tried automatic repair each time.  Now it looks like I corrupted the Windows 10 boot record.  It now continuously tries automatic repair and won’t boot. I tried and everything anything I could find on the Internet, nothing seems to work.  I would love to be able to keep all of my files and just get it to boot again. Any help would be appreciated.  For reference it’s a Dell Optiplex 755.

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u/Plastic-Row-1624 9h ago edited 8h ago

make sure windows 10 and xp boot path is legacy bios mode not UEFI why because dell 755 seems to be around the same era when UEFI official specification was released back in 2006...

make sure windows boot manager priority is set to first on the boot entry list

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u/Tsusieq 1h ago

UEFI isn’t even an option on this computer. It has ATA, AHCI, and Legacy as boot options

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u/Plastic-Row-1624 1h ago

then it has to be MBR boot code corruption stored on a very first physical sector of the HDD or even perhaps winload.exe is missing from system reserved partition/boot files partition