So yesterday I took my late 2011 Macbook Pro to the genius bar as for more than a year it has been performing very slowly. It takes over a minute to boot to the login screen then another minute or so after login before the dock shows. Even tying this i'm getting a spinning beach ball every now and then. The genius ran some diagnostics and said there was no issue with the hardware but that there is a problem with the file system. So as instructed i've repartitioned the drive to a master boot record then back to GUID, reinstalled the os to Lion then upgraded to mavericks. Tested it then and it took around 55 seconds to get to the login screen, then restored my info with migration assistant and it's gotten even worse. I also mentioned that two of the case screws were loose and he said he'd tighten them up, but by the time I got home one had fallen out. The machine is a 15", 2.2GHz i7, 8GB RAM, 500GB hard drive. Any thoughts on what else could be causing the slowdown. Thanks.