Is it safe to have two operating systems on a computer?

Technically yes. You can have dozens or even a hundred if you wish. At any given time, only one will boot and take native control of the hardware. Legally, you need to ensure you have bought authorised copies of the operating systems and applications, unless they are free such as with GnuLinux or FreeBSD among others.

Technically yes. You can have dozens or even a hundred if you wish. At any given time, only one will boot and take native control of the hardware. Legally, you need to ensure you have bought authorised copies of the operating systems and applications, unless they are free such as with GnuLinux or FreeBSD among others.