No display, no post, no bios
Well I just spent $1500 on PC parts and now that is all put together it won't give me a display, no post no bios, nothing.
every fan is working same the LED lights
Check that the RAM is seated properly. Do this with the power disconnected.
Disconnect everything except the RAM and video card (unless it has onboard video) and power button connection i.e HDD, ODD, USB etc and see if you can get into BIOS
Is there a speaker connected to the appropriate motherboard header pins at all? This may help to give you a clue as to what is or is not happening i.e beep error codes.
What is the make and model number of the motherboard?
Jayeff is right, disconnect everything that is not needed to boot in BIOS. Disconnect the hard drives(s), optical drive(s), floppy drive(s). If the motherboard has a built in video remove any other video adapters. Keep 2 sticks of memory and remove the other sticks. Connect the monitor and power up the system and be patient for a few minutes.
If you hear beeping or if you see indicator lights (power, disk, wireless, etc) blinking in a pattern then see if you can look up the error on the motherboard manufacturer's support page or user manual.
If you get the BIOS screen to start then check the settings. At this point add one device at a time, add the rest of the memory first and if it still boots then add one drive at a time. It is a slow process but if you make one change and the computer fails to boot, then you can undo the change and try something else. This will isolate what works and what doesn't.