Linux is Far Superior to Windows in every aspect, if your wife wishes to have an easy useful experience with linux, I would suggest installing Ubuntu 10.04 first, or just run from the Live CD f1rst to try it out. and use it til you get used to it then maybe upgrade to 12.04 or 12.10 because they have different interfaces(desktop) and are a little more difficult to operate and get used to, however 10.04 will be as close to Windows as you could get as far as ease of operating and intuitiveness with regards to how it works, unlike WIN8. Switched to Linux YEARS ago and have never regretted it, you won’t either.
What she is worried about is that she has programs that run some peripheral equipment such as her embroidery machines and a paper cutting machine. These programs were designed to run on a Windows computer and the computer controls the machines using the drivers supplied by the equipment manufactures. She also uses Firefox. What does Linux use to access the internet?