This post will help you if the Master Boot Record writes on the wrong drive when trying to boot from a device. You need to repair BCD/MBR.

This post explains What is a Boot Sector Virus which infects the Master Boot Record (MBR) and its prevention & removal techniques.

To access the enhanced security features of UEFI, Windows 11 will forgo the older Master Boot Record (MBR) partition scheme and instead use the modern GUID Partition Table (GPT) scheme.

Windows 11 PC won't boot? Microsoft's Quick Machine Recovery will automatically try to fix it before you have time to panic.

Some advanced technical knowledge was needed to create these strains as tinkering with a master boot record is no easy feat and could easily result in systems that didn't boot at all.