help me with a computer build?

[jasonzaps]

I need a new computer for around $800-$900 for gaming. it could be built or components

 

[CJb_432]

have a look at this build : http://uk.pcpartpicker.com/p/1MCBk

 

[C12Friedman]

...or this build based on the 4th gen Haswell processor http://pcpartpicker.com/p/1MHoh although it does use all of your budget. This system is unlocked for overclocking (which may be helpful in the future). I did not include aftermarket cooling for the CPU (needed for overclocking) since that can be added later when/if you feel the need for more performance
Or you can just go to PCPartPicker and play there to see what you can come up with but between CJB's Ivy Bridge build and my Haswell build I think you should have an idea of what can be done

 

[CJb_432]

Both builds are sound, ones cheaper, ones more expensive. Its your choice