I had installed Ubuntu inside Windows XP but then I formatted XP and installed Windows 7.

EDIT1: I used Wubi for the same. I want to know which one of the two will solve my problem? creating a virtual disk or resizing root? Also is resizing root possible as the 4GB ext4 partition is already in a NTFS format Hard Drive partition.

At the time of installation I had allocated only 4GB of space to Ubuntu. I want to increase that size as I keep getting a low disk space notification.

I have surfed through a lot of similar questions but this is not a duplicate.

Because I want to know a little about the file systems. In order to solve my problem,do I have to increase the size of root.disk? Or will it be solved by creating a virtual disk?

Also I want to know the difference between creating a virtual disk and just increasing disk space of root.I'm new to Ubuntu so I don't know how the file systems function.

EDIT2:I have created a virtual disk of 10gb ,but I'm still getting the same notification.Is there anyway to install all further applications on the virtual disk I created?