Asus P5ND2-SLI Motherboard
*Moth! erboard Revision : 1.03
*Motherboard BIOS Revision : 1.03

*VGA Card Vendor : ATI
*VGA Card Model : Sapphire
*VGA Card Chipset : Radeon x1650 PRO
*VGA Card Driver : n/a

*CPU Vendor : Intel
*CPU Type : Pentium D 805
*CPU Speed : 2.66Ghz

*Memory Vendor : Crucial
*Memory Model : DDR2 240pin pc2 5300
*Memory Capacity : 1GB

*Operating System : WinXP

[Problem Description]
System does not POST with no display visible, however there is no beeps heard at all, with or without the DDR2 memory module installed. LED green power indicator is enabled, cpu fan and
system fans are enabled. Have also removed and cleared CMOS battery and jumper settings but have been unable to access bios or boot up at all with nothing visible on new working LCD monitor graphics card and memory.

either a bad moboard or a bent pin on the cpu

You should ALWAYS benchtest a board to confirm that it works BEFORE installing it in a case.

Take the board out of the case, lay it on a non-conductive surface & test it. All you need is the CPU w/HSF, one stick of RAM, video card w/monitor, power supply & keyboard...nothing else. Then see if it will POST & you can access the BIOS.

Another possibility is that you have a cheap power supply. I notice you left that out of your spec list? What is the make, model, wattage & amperages on the +3.3v, +5v & +12v rails?

Thanks for the help. The power supply is an Xilence Power ATX 420W Model SPS-XP420

DC Output

+3.3V/+5V/+12V1/+12V2
Max Combined 400W

Orange +3.3V 29.0A
Red +5V 27.0A
Yellow +12V1 13.0A
Yellow +12V2 14.0A
Blue -12V 0.8A
Purple +5VSB 2.0A

Also, i have connected both the 4pin and the 24pin power connectors to the motherboard.

Follow Jam's advice and remove the motherboard from the case and bench test it. If you don't get the POST beep, remove the RAM and you should get error beeps. If not, you have a motherboard of power supply problem.

Probably the most frequent mistake people make with a new build is to install ram that isn't compatible with the mboard - in the worst cases, the computer won't boot at all when that ram is installed, and the mboard does not beep.

See response 5 in this for some info about ram compatibilty, and some places where you can find out what will work in your mboard for sure:
http://www.computing.net/hardware/w...
Correction to that:
Mushkin www.mushkin.com

"If you don't get the POST beep, remove the RAM and you should get error beeps. If not, you have a motherboard of power supply problem."

Incompatible ram is easy to test for.
Make sure there is a speaker (or speakers) connected so you can hear mboard beeps (on some mboards with onboard sound there are no case speaker pins on the mboard that work - you must connect amplified speakers to your Line out port and have them turned on - see your mboard manual).
Remove the AC power to the power supply, remove all the ram.
Restore AC power, try to boot.
If nothing else is wrong you will hear a pattern of beeps that indicate no ram is installed, or a ram problem.
E.g. Award bioses or those based on them - a a continuous string - a beep lasting about a half second, silence a half second, a beep of a half second, silence a half second, etc.

Connected to external speakers but no beeps with or without memory installed. :-(

"Connected to external speakers"

Not the speakers that connect to the onboard sound...the PC speaker that connects to the motherboard. Read your manual:

"System warning speaker (Orange 4-pin SPEAKER)
This 4-pin connector is for the chassis-mounted system warning speaker. The speaker allows you to hear system beeps and warnings."

"(on some mboards with onboard sound there are no case speaker pins on the mboard that work - you must connect amplified speakers to your Line out port and have them turned on - see your mboard manual)."

Most mboards have specific pins on a header you connect a case speaker to, or a few have a built in speaker or peizo sound making device on the mboard and you don't need to plug in a case speaker. If the mboard manual has no info about specific pins like that, and no built in sound making device, then you connect amplified speakers to hear the beeps.
E.g. I've seen this latter case on some Mitac mboards, such as all of those used in the Compaq Presario 74xx series.