I have Windows 7 installed on a Notebook. Because I wanted to experiment with Ubutnu without loosing my Windows 7 configuration I installed the Wubi Version of Ubuntu inside of Windows 7. Since things seam to work out well with Ubuntu and my harddisk space is very limited, I want to make Ubuntu my only operating system on this machine. So my question is:

Is it possible, to install Ubuntu 11.04 additionally to my actual configuration (Wubi and Windows 7)? And if things turned out well with the native installation of Ubuntu, too, to delete Wubi and Windows 7 from my system afterwards?

Why I am asking this is simply, that I am afraid, that if I just format my machine and made the whole harddisk available for the fresh Ubuntu installation, it could be possible, that it turns out, that one thing or an other would not work properly, like it did in Wubi. (Possible Network, VPN, and Firewall@work issues) In this case I'd like the possibility to switch back.