how can i set up adual booting system(windows'xp and Linux 7.2)?

Answer 1

It depends on the Distribution. Some Distros like Ubuntu will take free space from the windows partition and create a JFS (Linux file system) automatically. Other distros require you to already have a second partition (or hard drive) available for installation. You can use third party software like Partition Magic to create the necessary partition for your drive in case your distro doesn't offer an option like Ubuntu's
Most Linux Distros automatically set up a boot menu upon installation, so you can choose whether to boot Windows or Linux.
Hope this helps somewhat

Zach