Advent laptop keeps turning off and then a blue error screen help please?

ive got an advent ert2250 laptop which i bought from currys about 7 months ago the first one i hadkept turning itself of all the time so i got a replacement now i keep getting an error screen saying that an error has occured and the computer needs to restart keep it safe and then restarts it does this when i try to shut down and sometimes turns itself off with no reason like the power has gone i nearly always run it from the mains so it not a battery problem can n e one help i wanna take it back and get a new one coz i rely on it for everything and cant be without one