My ipod is flashing black and going to the power off screen? Never dropped my ipod, and did not get liquid in it?

I always make sure to take good care of my ipod, I have no warrnety, It has not been 3 years yer, never spilled anyhting on it nor did i drop/crack it. It happened randomly. Why would this happen...I have restored it tow times and yet happens, it flashes black and constanyl taking me to power off botton..

I'm really frustrated and can't afford another one..It was ios 4 something when i bought, bought it in 2010 march