[PLUG] Query regarding installation

[Vinayak Merwade]

Hi
First of all I wish you a belated new year greetings .
 I'm going to install Linux in my system .
1) I would like to know that whether I have format my disk for this reason ?
2) I want make dual boot i.e. both dos and Linux
3) Or without harming the earlier installation can I do the same?
4) I have 80gb hdd, I can keep 10-15 gb free for linux installation
(as my main work is on widows platform but due to other work i have to use
linux)
I need your help!

Vinayak Merwade.