DaVinci Resolve is probably the most powerful free NLE out here.
Still not close to AVID power for serious editing and a bit behind Premiere and Final Cut but Black Magic is really pushing the envelops here.
Plus it's a kickass Color Grading software and possess an integrated solution for Fusion composition which is also, a free Compositing Node structure software.
I use it daily for Color Grading but it's solid enough for a free NLE and gets tons of support and updates every months.
Its interface is very close to Final Cut, so if you're used to it, you might just love it.
https://www.blackmagicdesign.com/products/davinciresolve/
EDIT: NVM, just checked it's not available on Vista
For anyone on 7, 10, Linux and Mac OS, It would be the good to go software.