How to remove Administrator(not me) and file being locked even thought my MacPro is one week old?

Hi guys, Recently I just bought MacBook Pro Retina 13". After that I found out I got Remote DIsc Which I can never look or see thru or even delete it. There is more, with world Icon called Network but i can;t so anything. At the same time, when I checked owner or permission of my own Local Hard drive or folder, it was locked and I can't even allow to untick it. Even worse, in "get info" permission for Read or Write is occupied by "Administrator (Clearly not me since i can't change anything at all), Wheel, System" and every time I set password and trying to changed the onwership, the cursor frozen, Finder frozen, everything frozen. I can't even force quit them so I have no choice to pressed power button to restart and when log in, the loading bar will stuck in the middle or somewhere and it won't move (I fell asleep till afternoon and still the same) until I reinstall the OsX Yoesmite. The installation took me sometimes over 100 hours. That processes were happening again and again like a life cycle. So I can't even restart or shutdown my laptop ever otherwise it will stuck during boosting. I tried everything SMC, Safe mode, Restart DIsck, Reovery, Disk Utilities it doesn't work. Every time i checked my Activity Monitor, weird things like itunehelper, MirgrationAssistant, KernelAissistantManager, ScriptAssistant, and other apps that I did not run. It even sometime stop me from using my own wifi from broadband. Can anyone hlep me please. I am losing my mind . . .Please