Dual Boot even after installing earlier versions of Windows later

One can have dual boot option on PC to boot multiple operating system on single computer. 

For example, you can have Windows XP, Linux, Vista, Windows 7 etc on single PC by installing them in different partitions. But to have that dual configuration, you will have to install the latest version after the earlier ones. For example, you can have dual boot option if you have installed Windows 7 in different partition on a PC with already installed XP. But if you will install XP after Windows 7, boot screen will not see any option to start Windows 7. But there may be a situation where you need to install Windows XP on your pre-installed Windows 7 PC.

Use Windows 7 without Activation

Hey friends, I am blogging after a long long time.I was busy with my exams and so didn't have much time to put on a post. In this comeback post I would like you to tell you how to use Windows 7 for 120 days without buying any activation key although the original trial provides you 30 days of trial.

1.) Open Command Prompt by clicking on Start then in the search box type cmd.

2.)We need to use cmd with administrator privileges, so right click on cmd and click on run as administrator.