I will try to help you with your system building or modding, if you choose to build one yourself.  System building can be fun, & the satisfaction you get when you switch on your DIY system can't be described.  I will try to address some common problem & questions, like which motherboard (mobo) to choose & what graphics card to use.  These are of course should be taken as a guide or recommendation only, based on my experience

AMD Systems building guide

Intel Systems building guide

Fan & Cooling guide

AMD Over clocking guide