Before starting we must be familier with the following terms :
Host operating system (host OS):
the operating system of the physical computer on which VirtualBox was installed. There are versions of VirtualBox for Windows, Mac OS X, Linux and Solaris hosts.
Guest operating system (guest OS):
the operating system that is running inside the virtual machine. Theoretically, VirtualBox can run any x86 operating system (DOS, Windows, OS/2, FreeBSD, OpenBSD).
Virtual machine (VM):
When running, a VM is the special environment that VirtualBox creates for your guest operating system. So, in other words, you run your guest operating system “in” a VM. Normally, a VM will be shown as a window on your computer’s desktop, but depending on which of the various frontends of VirtualBox you use, it can be displayed in full-screen mode or remotely by use of the VirtualBox Remote Desktop Protocol (VRDP).
Its a special software packages that are shipped with VirtualBox. Even though they are part of VirtualBox, they are designed to be installed inside a VM to improve performance of the guest OS and to add extra features.
In this case we will be using Ubuntu 10.04 as host OS and windows 7 as guest OS. Just download the Virtual box latest version from http://www.virtualbox.org/wiki/Downloads. Double click and install the virtual box in ubutu 10.04.
After installation start the Virtual box and Click on the New button and start the set up
The Virutal Box wizard pop up and guide you through the set-up that is needed for installing VM.You’ll need to tell VirtualBox what operating system you want to install. While the software can handle all kinds of versions of Windows – as well as Linux, Unix and even OS/2 – you’ll want to select Windows 7 in this case. Give your virtual machine a name on this screen, too. Click Next.
Here you need to allocate the memory to the new (Windows 7) virtual machine. Depending on the amount of RAM installed on your system, you need to select the memory size. Since Microsoft recommends minimum of 1GB RAM for Windows 7, enter 1024 MB in the right-side box. Again, click Next. (Note : The setting can be changed later also. You are not supposed to give more than the half th size of RAM in host machine.)
Now you’ll need to set up the virtual hard drive, which is a file that mimics a physical disc. Leave the settings here at their defaults and click Next.In this case you will be creating new hard disk.
You can choose the type of virtual drive as you want. I will choose dynamically expanding drive, which starts out small and grows as needed. This takes up the least amount of space on your real hard drive. Alternatively, you can also select Fixed-size storage. As the name indicates, fixed size storage doesn’t grow. Once again, click Next button.
Select the size of the virtual hard disk. By default 20 GB is allocated. Since Microsoft recommends 16 GB of free disk space for 32-bit & 20 GB for 64-bit Windows 7, let’s use the default 20 GB as the virtual disk size. However, you can change it if you don’t have enough free space. But make sure that you have allocated 16+ GB. Click Next and then Finish to finish virtual disk setup.
You’ll be back at the screen where you started, which is called the Virtual Media Manager. Make sure the Windows 7 virtual machine you created is selected, then click the green Start arrow.
Select the media you would like to use for installation purpose. Select Image file option as media source as you are using Windows 7 ISO file to install. If you have Windows 7 DVD, select Host Drive letter as your DVD drive. Click Next and then finish to begin the installation procedure.
Windows 7 installation process will start in a few seconds. Just follow the onscreen instruction to finish the installation procedure.
You have now installed Windows 7 on VirtualBox. Have fun with Windows 7.
NOTE : In some case windows 7 will freeze And it will have problems in creating a new virtual hard disk. In this case go to settings – > Click storage -> delete the SATA controller and add hard disk (window.vdi) in IDE controller.