Windows has Secure Boot as a security feature to ensure only trusted software loads when you boot up your PC, combating any malware that tries load.

In Windows 7 and Windows Server 2008 R2, you can native boot from a virtual hard disk without a hypervisor In response to my posts about managing multiboot with Windows 7 and Linux, Microsoft IT Pro ...

The message Windows Boot Manager has been blocked by the current security policy means that the computer’s firmware is stopping the bootloader from starting up because it does not meet the Secure Boot ...

If your Windows PC's Secure Boot certificates are out of date, your system is vulnerable to malware like rootkits.