All Applications close in my Macbook Pro

[chicagosouth1]

I been strugle because all applications close unexpectadly in my macbook pro... It's 2.53GHz Intel Core 2 Duo, it has 4 GB 1067 MHz DDR3... 320Gb HD, The problem not always happens but it does ever since i bought it, i bought it at Best Buy, i brought it back a couple weeks ago they tested but it is suposted to be fine...
I use my machine for DJing so I hope you guys can help me to resolve this issue...

 

[iLog.Genius]

The easiest thing to do is perform an Erase and Install. Clean wipe the whole HDD and reinstall the OS. That will basically tell you what the problem is, software or hardware.