Im wondering can i use linux if i already have windows installed? and which version of linux would be the best to use?
Yup, linux will install next to Windows without breaking it. All you need for a fully functional distro install is like 50 GB of empty storage somewhere.
Best to use, there is no such thing, linux is not like windows, it's not a one-size-fits-all kind of deal. An easy start would be something like Manjaro XFCE, which is very easy to use and stable. Or Mint on Debian with Gnome is also nice, or Fedora 19 Gnome, or OpenSuSE 12.3 KDE. There is a lot to explore, the GNU/Linux universe is infinitely richer than the Windows software console phishing tank, take time to explore, just start with one distro, try others when it doesn't work out for you, try other DE's, try other applications, everything is gratis anyway, so it doesn't cost anything to try everything.