I have installed and using Ubuntu with Wubi installer inside Windows7 as a dual partition.
Now I want the same OS image to be loaded using the Virtualbox.
Is this possible?
Alright, this is going to get a little technical. Plus you're going to need a spare partition or disk.
To start with, backup all your data on both systems. Accidents happen easily. Clonezilla is good for making copies of everything such that you can put it all back if you wipe out your disk.
So, find a USB drive, or disk partition with enough space to hold your wubi install. Then follow the manual instructions at http://ubuntuforums.org/showthread.php?t=1519354 to move your wubi install to that space. Read carefully and make sure you understand how it all works before trying it.
Once you have your install migrated into the clear, the simplest thing to do is to fire up Clonezilla ( http://clonezilla.org ) and make an image of it. You want just the Ubuntu install, not the Windows install too. Then fire up Virtual Box with Clonezilla. Put the image in a Windows shared folder and configure Virtual Box's network settings so that you can access it. You should then be able to tell Clonezilla to connect to the share, and restore the image to the virtual machine.
Personally I've only ever done it this way once. It's a pain, and not worth it.
Easier way: Do a clean install into Virtual Box, then fire up your wubi install. Log out of the graphical shell and hit ctrl+alt+F1 to get a terminal prompt. Log in to the terminal and cd to /home. make a tarball of the user home folders with tar, and save it to your windows system, which will be mounted under /host. (There are plenty of good sets of instructions on using tar elsewhere, so I'll just say tar --help for the rundown on the options)
I usually do the same thing with the contents of /var/cache/apt to save redownloading updates to the new system.
Then, go back to Windows, fire up Virtual Box, put the tarballs in a shared folder where you can get to them from the VM, and expand the tarballs back out into the directories from whence they came. That will get all your personal settings and the packages for all the programs you had installed, so you have essentially the same install, only with fewer reboots and much less chance of accidentally nuking your disk.
Yes this is possible. For that you need
This process is very easy. Go through this link: Installing Ubuntu in Virtual Box.