Is This Normal?

[LiamPK]

So, I'm playing a a old game which takes up little RAM etc and I am listening to a web stream, I ALT CTRL DELETE to end the old game, then all of a sudden my PC suddenly restarts and I says windows has encountered a serious error. Does this happen from time to time or should I be worried about my power supply or motherboard?

[GeForce]

Id say it was the game, a lot of old games I know have problems with minimising or "atl-tabbing" etc, I wouldn't be worried.