Gpu Doesn't work anymore

i bought my brother a gigabyte 7750 from canada computers in august so he can play guildwars 2. it ran smoothly for a few months, then my brother quit the game. then my brother wanted to play another game, and it wouldnt run. and when i boot up my pc, it says i dont have the drivers, but i do... the computer gets loud and the back of the case gets super hot. so we didnt bother anymore with games. then i did research, found out the card needed 400w, and my psu only has max of 250w. could the psu be the problem? if so, why did it run fine for few months before? if anything, could the card still be used in another computer if i were to build my own comp? 

Hmmm odd, the PSU could be the problem. As it was running fine, it may of had the PSU nearly maxed, which in turn wears them out pretty quick. With the size of the PSU it does sound like that could be the issue depending on what other hardware you are running (eg CPU, mobo, multiple HDDs)

Although you may wish to test the GPU in another system if you can.

- zanginator