Really bad performance issues on a gaming pc?

So I recently got a message saying my computer is low on memory and literally 2 minutes after that popped up all my programs have been crashing. Then when I try to record with Fraps on minecraft it crashes and for me minecraft runs smoothly but right as I hit F9 (which is to record) everything crashes. My PC specs are down below I don't remember the exact name of my motherboard. (FYI I custom built this pc)
AMD A6-7400K
8GB 1866 Ram
MSI motherboard
500watt powersupply
Diablotek case
This is so frustrating I'm trying not to get mad but its really not that easy espcially when you put alot of time and effort into something.
I've had this built for over 2 months now so today it has just done this so its really confusing.

Added (1). i also got a 120gb ssd and 1tb external hdd

Danny 07.11.2015

Causes: Too many programs running at same time. Limit that by not opening so many, and by limiting the ones loaded on power up with msconfig.exe.
Also not enough storage capacity. Leave at least 25% open space on the hard disk. Send files to other places: USB storage devices, other hard drives, Internet storage, burn data DVDs.

Starrysky 07.11.2015

You can't really call that a gaming. Sounds like a free space issue or maybe virtual memory is turned off. Maybe some of your ram isn't working or something. Could be the ssd is full and its trying to put temp files there

nostrum 07.11.2015