Building a Computer

[ConnoR]

I was thinking off building a new PC but wasnt sure how much i would need to spend to get a half decent one. I wont be building one for a while yet, but i thought i would look around. I will be spending around £400-£500 but could do with buying a monitor aswell but if i cant get a decent PC as well as a monitor for that price range i have a monitor i could use. I dont want the best PC in the world but if i can get 333 fps on all maps on low settings, and it runs COD fine as well as being a decent PC for other things i dont mind. Thanks in advance

[ConnoR]

Well at my Dads house i have a oldish Dell PC with a decent size case. And i have the power supply etc. But i would need to completely rebuild most of the pc because its a bunch of crap. Like a new mother board and ram and everything