how to create a ext3 system file formatted disk to install ubuntu?? please help?

Answer 1

The installer does that for you. Unless you are trying to dual-boot it, you needn't worry about that. Even if you are dual-booting, try using the "Guided - resize" option to shrink your Windows partition.

Read this if you feel you need it:

http://www.psychocats.net/ubuntu/installing