Try this to see if you get any kind of POST beep error:
 
1) Remove all the expansion cards, this means graphics, sound, lan, modem, etc....
 
2) Remove all sticks of memory...
 
3) Disconnect all drives from the power supply, leaving only the motherboard ATX power connected.
 
4) Disconnect all data/ribbon cables from the drives.
 
5) You should now have a stipped down machine with only the power to the ATX main connector, the CPU and Heatsink/Fan on the motherboard. Any onboard items is ok as we're trying to troubleshoot down to a specific item.
 
Now what should happen is one long beep indication that either the memory is bad or can't be initialized properly. This is what we want to hear. This would indicate that the motherboard/bios/cpu are being detected properly.
 
Now insert the stick of ram after powering down the machine and unplugging it of course, and then power it up and see if you get any other POST beep error code.
 
If not and you only get the fans to power up then I'm going to suspect bad or incompatible ram.
 
If you get another, different post beep error, it should be one long and two or three short beeps indicating that the graphics card can't be found or initialized.
 
Now if you've gotten this far try installing the graphics card and repeat. Keep doing this until you find the part that isn't allowing your machine to post.

ok plugged the speaker in
 
and unplugged all the data cables add on cards and hard drives and cd drives and also took memory out
 
still nothing - no bleeps
 
also reset cmos again
 
nothing

Then I have to suspect one of three things, the power supply, the cpu and/or the motherboard.
 
Do you have any other known good parts to check this out with ?!?
 
If not then it maybe difficult without finding a shop that can help you out here or some other kind soul perhaps

the power supply is also new
 
i could try an older power supply in there

ok tried different power supply and still nothing
 
totally pi**ed off

Then all you can try now is the CPU on another motherboard and/or another CPU on this new motherboard

might aswell put my mind at rest and give it a go!

i had a problem like this one time my friends computer. Turns out he put one to many mounting posts in the case and the extra one grounded out the motherboard and fried it.

I hope im not getting too basic here, but have you made sure your brightness and contrast controls on the monitor are set correctly? Thats the first thing to check for a black screen.
 
You also didnt mention if you installed a new OS or if swapping HD from one system to another.

Had a computer once acting similarly. Reset button was stuck. Unplugged the cord and everything was fine

Pull th motherbord out of the case and run it in midair while you hold it. this will determine if you had something grounding out. I'v seen this a few times.

well i called the company today and they said send the processor and motherboard back so that is what i have done, when i get a replacement or have the same ones sent back if there is nothing wrong with them i will test them out of the case first
 
the monitor stayed on low power standby so it wasnt a case of brightness settings etc
 
Nick