Monitor No Signal..need help

My buddy recently purchased parts for his new comp.
We put it together and everything seemed to work fine...we started installing windows XP on it only to realize that we need SATA controllers for his RAID hard drive.
We went on another computer and created the needed floppy only to come back to locked up system.
The computer boots up but it doesn't go into any sort of screen... in fact the monitor displays NO SIGNAL.
We checked all the cables...no bent pins...no motherboard beeps!!!!
Replaced graphics card...no luck...unpluged/pluged all of the things except taking out the CPU...nothing.

I should mention that we frequently were taking the floppy drive in and out of the computer because we had one floppy drive and would go back and forth between his old computer and this new one.

It worked fine. We shut it down, turn it back up with no response.
Please give us some suggestions.
Thanks.


His components:

CPU: AMD Athlon XP 3000
MB: Asus A7V880
RAM: 1GB of Crucial (checked motherboard manual for compatability and
it was fine)
Graphics Card: Radeon 9800Pro 256 mb
Case: some sort of gamers case with a 420W power supply
Hard Drive: Western Digital 80 gig
DvD burner
Santa Cruiz by Turtle Beach sound card

 

You were removing the floppy drive while the machine was powered up?????

How do you know the machine is booting.....does it post (a single beep)....are all the fans spinning up.....optical drives lighting up on POST

Tried a different monitor??????

Remove everything except the CPU/FAN.....does it beep now?????

 

Of course not..we turned everything off and even unplugged the power out of the wall when removing the floppy drive.
Optical drives were reseting on boot but not doing the boot beep..
Fans are all spinning and we have tried a different monitor but no luck.

Have not try removing everything except CPU and fans but have tried removing component by component....take out one stick of ram, boot, nothing...take out the other one, boot, nothing...take out the graphics card, boot, nothing...etc

 

we also took the graphic card off my other computer and it did the same thing....

I took the graphic card back to my old computer and it works
What happened is that it worked at the first boot up. Then we tried to install the drivers for my SATA hard drive and we unplugged the floppy drive to go to my old computer so that we can create a disk off the cd for it.
and when we came back the monitor wont work anymore. Iv been waiting for asus phone call for about 3 hours now, no joke, I called em 3 times they tell me that they are busy....
I need some help NOW.....
thanks guys

 

I seem to be having the same problem.
I turned off my pc, everything was working fine. Same Mobo.
When i turned it on next like 3 hours later first it wouldnt start either video or cpu fan. Cleared the CMOS thinking it might've been a voltage thing that mobo took as overclocking. That worked as for the cpu, but i still get no video feed. I dont get the first beep so i dont think its posting. I stripped it down to nothing, and the only time it beeped was when i took everything including ram (3 beeps). If i put the ram on it doesnt beep. Its driving me crazy! what can we do?