Do I have a dead motherboard? No beep, no BIOS screen.

Did it run fine before or this a new build? Please list your system specs especially the power supply and video card.

Make sure you reseat the component such RAM, video card, power cable, and data cables (SATA and IDE). It will solve the problem however if not success, try reseat the CPU if suspected.

If your PC are new build, make sure the component are properly installed.

If your PC are old (or maybe no longer used), I'm not sure what causes it, but the POST diagnostic card can help you find the cause. If possible, replace some component (such RAM, video card, etc) if you suspect some component are dead.

I have checked all of my components(RAM,videocard,power cables,sata,harddisk),all are working fine on another pc.i checked my processor too.but i still don't get boot from my pc.Can i have question for u.Except these components which component is most likely doesn't work in my pc.By the way i ordered a new motherbord.

Does the PSU power up?
If the power supply does not run then you might have the mains power turned off or the PSU is dead.

yes sir my PSU power upes...

Try using the Power on self test diagnostic card, it can help you to fix it....

If there is no screen or no booting then how will self diagnostics test run....

Do any fans start spinning or do any power leds turn on?

I have the same problem on an older ASUS IPLP-LC board. Replaced memory and replaced thermal grease with fresh coat. No video or nothing! It was running fine.

thanks man but i tried what do u say but it's not working in that way....

another overlooked problem is grounding... make sure your components arnt grounded out

First of all...

What brand/type Motherboard do you have?
What kind of Dram?
Same for the type of CPU, i'm curious  

Did you try the hardware BIOS reset? (placed with a jumper on your motherboard)