Samsung Galaxy S4 — s4 firmware issues and lollipop update help pleeease

Hello everyone, I'm new to android and I have a second hand s4. If my battery goes completely dead I cannot turn it back on unless I use recovery mode and factory wipe. The phone appears to be a google play edition but when I turn it on I get the red and yellow notifications in the top left at boot plus clockwork mod is the recovery mode. There are also certain things I have done on the phone which have led to me being notified I may be using a rooted device. I have since done a check and it appears that it isn't rooted so I think somebody has messed with the device in the past but have no idea how or why. All I want to do is have a nice fresh install of lollipop and hopefully all my issues will be resolved. As I say I'm new to android so I'm not up on all the terminology yet but I would really appreciate being pointed in the right direction. Thank you

— modified on May 4, 2015, 1:17:13 PM

OK after a bit of scouting around I have installed kies on my laptop to check for a lollipop update. The problem now is that it won't let my s4 connect, I have the necessary drivers installed but after waiting to connect for ages I get a message saying I need to reboot phone and try again. No luck with that at all and I have even tried the factory reset in my recovery mode. Somebody please help as I don't know where to go from here.