I want help in building a gaming computer
budget of 2500.00 u.s. dollars
I am  starting with a cool master box.
Nvidia g force 295 video card ( 2 )

I recommend that you go to newegg and use it to build.  start with your processor and then match motherboard, RAM, vid-card slots, hard-drives, etc.  Make sure that you do the power supply last, as you need to figure out how large a PSU you will need.

PSU calculator <-- this is a handy tool to see what you need in terms of power based on what you are putting in your box.

Hope this helps  If you want any other advice, PM me or try to get me on TS in the next couple of days.

yea, instead of starting with he vid card, start with the most expensive piece and probably most important piece, your CPU.

actually, I said CPU because when you choose a motherboard, you need to make sure that your CPU will work with it.  This can be a bit of a hassle if you decide on an Intel chip because even if the socket is right, the board may still not work with a CPU, because the board may be configured for a different series of chipset.  

The internet is your friend in this situation, there are reviews and guides to just about all of this.  A word of warning though, be careful when reading user responses, as you have stumbled into the world of the fanboys, and everything that anyone says is more heavily stilted then their political views.

$2500 US will build quite a system.

I always write an outline of what I am looking for:

X GB RAM
X Ghz Processor
Which Video Card

Those are my big three.  I fill in from there.

I also figure out what I can use from my previous set up so I know what not to include.

A good solid motherboard that allows room for upgrade and a versital roomy case get determined once I know my big three.

Everything else fills from there.

However, again, $2500 US will buy a really nice rig.  Especially if you are able to bring forward anything like a monitor, RAM, etc.

And, I would recommend newegg for your purchases.  They are really good on RMAs if you need it.

Good luck.