macbook pro shutting down at apple logo screen

Hello, I have a mid 2009 macbook pro that I use for work everyday. I have had a few issues with it over the years but I have always been able to fix it. I have had to replace 2 hdds as well as the wire connecting the hdd to the motherboard, but it has been running perfectly for the last year since the last issue. It is currently running mavericks, I have upgraded it with 8 gigs of ram and a 250gb ssd when my last harddrive went. Yesterday I was doing some work when my computer became extremely sluggish. I attempted to restart and it would boot to the apple logo screen and then just shut off. Please note that it would not hang at this screen, and there was no progress bar below apple logo, it simply shut off. I had a cloned hard drive that I made last time a hard drive went on me, I connected this via usb and the computer booted up with no problems. I then put this into the machine figuring my ssd had gone but again it would not boot up. I then connected the original ssd via usb and booted from here and the computer started up with no issues, and ran stably for at least an hour while I backed up data. I figure since both hdds are booting fine from usb and neither works when connected in the computer that suggests that it is a hardware issue (but not hard drive) rather than software? Also note that it was running fine for sometime before this suddenly occurred, and I had installed no new software at all recently. Has anyone experienced a similar problem that may be able to point me in the right direction?

Thanks