Whats SevenLight v3 Final?
If I am not mistaken, SevenLite is like XPLite.
Its a tool that lets you modify a Windows installation, to change installation features, merge service packs onto the disc, remove useless features like drivers you don't want, and add other tweaks. It lets you customize the installation disc before you install the OS!
I used XPLite when installing Windows to my EeePC netbook a few years back, so I could make it take up less space on the small 4GB SSD hard drive.