Windows Vista is hands down the most user friendly version available.
I had no problems teaching my 82 year old Grandma how to do it. I enjoy that everything can be coordinated as one lump sum, and it keeps organization at a maximum!

I love my Windows Vista on my Dell Studio Red Laptop. Knock on wood, I have never had a problem with it crashing or being slow. A lot of that happens due to your internet and it's speed. I love it and wouldn't upgrade to Windows 7 or 8.