Hi I have been using linux and unix for many years long before it was popular for home pcs.
I used to use Ubuntu but found the new desktop layout not very useful.
On my laptop and also my partners I made them dual boot. That is at start up you can choose if you want the pc to start windows or linux. I would recomend linux mint.
my partners mother (92years old) uses linux mint.
To test it out it can be burnt to a cd and run from that without effecting the pc. it will be a little slower on the cd of course but will give you a taste of the system. Using a re writable cd you can try different linux versions.
My email should you need any other help if i can is is
[email protected]