Major hard disk errors, cannot erase or repair disk

I have been having issues with my MacBook Pro 13 inch 2011 model. I have tried putting it in recovery mode, but now it will not load completely. It shows the status bar is fully loaded, but it will never take me further. I tried using verbose or single user mode to repair my disk, but now the computer screen splits when I try to enter anything. I know that my disc is messed up and I'm trying to fix it. It would not let me a race it, nor repair it. So now I'm just wondering should I buy a new MacBook altogether or should I even try replacing parts or furthering my repair/damage. I get the Utility disk error: POSIX: cannot allocate memory, which has been suggested to replace the SATA ribbon. The initial message I got said that the S.M.A.R.T. Status was failing. I have no idea what to do at this point I think I have tried doing everything but replacing the ribbon, but I want to make sure that I don't waste my money on a ribbon & time doing so, when it's not going to work with my issue. I also have tried reinstalling OS X 10 from the Internet and that did not work, so then I tried installing the OS X base system, but I can't even do that