I looked your mobo model up, Your motherboard can fit pretty much any gpu because it has a pci 16 slot as long as it's not too power-hungry because your 450 watt psu. Also you have any more details on your cpu I couldn't find anything on the g240. Like number of cores and ghz and like is it an i3, pentium, i5 ect... also how much ram do you have in your pc, that's important to include, and what do you plan on doing with this pc. I can recomendation a gpu if you answer these questions, i can't give you a good recomendation if i dont know a lot of your pc specs.