MBP boots up, but applications or menus are not available
I have a MBP 15" that I got back in 2011. Anyway, I swapped the HD from the stock 500 GB one to a 256 GB SSD and also upgraded my ram to 8 GB total. It was working fine for the longest time but until a couple weeks ago, when I start up my computer, it will start up fine, and it would open an app that I have automatically start on start up, but then I can't do anything else. When I quit the only running app, the top apple menu also disappears and I literally am just looking at a blue screen. My SSD is about at capacity in space, I don't know if that has anything to do with it. I tried plugging in my external TB HD but it still does the same thing. Someone please help! Thanks much.
Is this a good question?