The possibility of simultaneous operation of a personal computer under the control of several operating systems does not yet exist, therefore it is impossible to switch between them in the usual sense of this action. However, there is a choice of OS at the stage of starting or restarting the computer.
Instructions
Step 1
By default, the operating system is selected when the computer is turned on, after the end of the basic input / output system - BIOS. Therefore, to change the OS, you need to initiate a restart of the computer - in Windows this is done from the main menu, opened by pressing the Win key. After the start of a new boot cycle and a list of systems installed in the computer appears on the screen, navigate through its lines using the arrow keys, and make a selection by pressing the Enter key. This menu is displayed for 30 seconds (the timer is also present on the screen), and then, if the user has not made a choice, the default OS is loaded - it is the first in the list.
Step 2
If this menu does not appear when you boot your computer, it is most likely disabled in the settings. In this case, use the boot protocol controls built into the operating system. In Windows 7, to do this, first press the Win + Pause key combination, then click on the "Advanced system settings" link and on the "Advanced" tab of the new window, click the "Options" button in the "Startup and Recovery" section.
Step 3
In the next open window with the settings, check the checkbox next to the "Display a list of operating systems" and select the length of time to wait for user selection in seconds. After that, click the OK buttons in the two open windows and you can proceed to reboot to select the OS change.
Step 4
Simultaneous operation of two operating systems in one computer is impossible, but there are programs that, under the control of the main operating system, imitate the actions of the other. If you install such a "virtual machine", you will be able to switch between the main OS and the simulated one without using the computer restart procedure. You can find software for implementing such a scheme on the Internet - for example, it can be VMware or Connectix Virtual PC.
