I my system I had completely messed up in installation of Windows. What happened here that to text Ubuntu I had installed same on a different partition. I am not so expert in it but I just follow the wizard. Now the drive ubuntu is installed is invisible in Windows 7. My Windows 7 is now crashed and I will need to re-install the OS again. Here I need to ask that does Windows 7 deals with ext3 type format drive for installation. I just want re-install by formatting everything back.