Why does my computer just shut off while I am using it?

I have a Dell Vostro 220 and my computer would shut down for what I thought was unexplaned.While checking all my different cables I happen to slightly touched the power cord that was plugged into a 6 plug surge protecter that also gave me 3 more feet to reach the wall outlet and off went the computer.I have the same surge protecter upstairs with my HDTV and sound system To conferm it was the protecter I gave the surge protecter a little touch and off went the TV.Also if you have any maintence programs set to run some third party utilities will automaticly shut down your PC when there done running.So unless your about to expirence a motherboard meltdown,check the little things.If it is the plug,gently bend the plug prongs just a little to give a more secure fit.It worked for me.

Apparently seems like your laptop is facing heating problem & its because your cooling system including fan is not working properly. You need to check if your fan is running at adequate speed and also there aren't any dust particles stuck in head sink on either side of your laptop. All you need to do is just to use an air blower and clean the fins of your heat sinks to make the air flow properly. Good Luck