laptop power

[pepzsoduh]

earlier today the power cord for my laptop stopped working so i told my mom to get me another on the way home from work. i made sure she got one that was compatible with my computer and when she got home i plugged it in and it worked for about thirty minutes then suddenly stopped, i took it out and plugged it back in and it came on for a second then went out. it does this whenever i plug it in, could the problem be with the computer, or maybe a heat issue?
help?