I wouldn't suggest to get rid of windows in a 100% There are some applications that you might still need and they would be available at the moment only for windows. Perhaps you could reduce the volume in the windows partition to use 30% of your hard drive and use 70% for a Linux base OS. Use an application such as Gparted to split your hard drive
When installing a Linux base OS make a partition about 15 or 20 GB for the root of your operating system, a partition about 2 or 4 GB for swap and the rest for your data files. The installer will format these partition at installation time, if you need to select the file system type select ext4 which is the recommended one at the moment.
Select an operating system such as Debian (http://www.debian.org/
) for its stability
When downloading Debian there are a bunch of files you only need the first image, the rest are packages that you can install later.
I would suggest you to install two graphical interfaces the one by default in Debial will be Gnome, But I would install also a light weight GUI such as Xfce and test your computer with both of them. Just to see wich one run your computer cooler.
Another distros to download and try atleast as live sessions are
OpenSuse -----------> http://www.opensuse.org/en/
Fedora -------------> http://linuxmint.com/
Good luck to you.
Note: Another reason why I think is a good idea to keep windowns is if in the future you would like to sell the computer you can boot in windows and press the key combination to set your computer back to its original defaults.
Or if you would like to upgrade the BIOS software in the computer usually vendors make these upgrades available for windows only.
But it is your computer so you should do with it as you please