I bought a MacBook Pro 2012 model (13'', 4GB RAM, 500GB hard drive) back on the 24th of July and it wasn't until Thursday that it started running slowly. By slowly, I mean (basic) applications take around 10-20s to load. Even trying to pull up the option to shut the computer down takes ~15s. I opened up Activity monitor and there is no problem with the CPU, System memory still has 2.25GB free, I still have 387 GB of hard disk space free, but when I open Disk Activity, I get these occassional red spikes (peak: 230kb/s). I have no idea what the problem is.