RAM missing and strange serial number
Hello.
First of all, this font is amazing what is it?
Lets get to the problem,
Yesterday I started up a friends computer ready to play some games together, and it was like a rock trying to move up a hill, you get me, it was super slow. About 10 mins later it turned on and signed in with all of his icons gone so we had to wait another 5 mins (he has 15 inch retina macbook pro) then everything loaded and we played some games. My macbook was getting 30 fps while his was getting 1 fps. He said that usually his computer has 60-70 fps and this was not like normal.
My inner computer lover started to diagnose it when I saw that Physical Memory in Activity Monitor was only 4 gbs. I checked in System information and it says 4GB Installed, one slot with 4 gb and the other empty (not in use). I noticed something else as well with the serial number, it says "-1". I KNOW his serial number is not supposed to do that.
Any help will be appreciated.
Noah (My friend Tom's computer)