I suspect you transfered your old user account with migration assistant instead of setup assistant when you first logged into the computer. You probably are not logged into the user account your transfered your data from. Open Systen Preferences and go to the Users & Groups tab. See if you have any other users listed there. You will probably need to log out of the current user and into the user account that you transfered.
Yeah I didn't do it when i first logged on, I did do it afterwards, and I used the whole migration assistant
But no, I dont have any other users
I only transferred a few things; it was only the group of "My" things; "My Photos, My Videos, My Music" etc.
All I wanted was my music to be honest haha
But yeah, there's no other users on this computer, there's the Guest user but that's it :/
Well then, I can't really say what happened. With migration assistant, you can't transfer a user account to the same user id you are logged into on the new computer. That's how I remember it anyway. So, it seems that if anything transfered, you should have more than one user on the computer.
Maybe double check the user folder on the hard drive to be sure. Check the size of the music and picture folder to verify nothing is there.