If your motherboard does not post, try these things...

1) Check memory.
Reseat memory by removing the memory from the motherboard and snapping it back into place.

2) Clear CMOS. 
On your motherboard is a physical "jumper" or switch that brings the motherboard CMOS settings back to defaults.  CMOS is the data part of your BIOS where settings for your hardware are stored.  Refer to your motherboard manual to find the jumpers that control RESETTING the BIOS.  |

3) Check the processor. 
Carefully remove the processor from the Socket and put it back into the motherboard. 
MAKE SURE that the CPU Heatsink and Fan are attached correctly.

4) Reseat your Video Card. 
Remove you external video card and reinstall it.

5) Remove the motherboard from the case. 
Try to post the motherboard outside of the case to eliminate the possibility of “grounding” problems.  Place the motherboard on some NON CONDUCTIVE surface and connect the appropriate ATX power connectors.  Find where you would connect the “Remote Power Switch” to turn on your motherboard.  If you short these two pins out, it’s the same as “PRESSING” the power switch on your computer.

6) Check power supply. 
Check the switch on the back of the power supply.  Remove the ATX Power Connector and make sure your “4-Pin” or “P4” connector is also plugged into the motherboard. 
Most modern motherboards utilize both a 20-Pin ATX Power Connector in addition to a “4-pin” P4 connector (normally yellow and black wires).  Some SLI and other motherboards also utilize an additional 4-pin power connector that is branched off of the main power supply, but is only required when using TWO SLI Video Cards.

7) Try different memory. 
Not all memory modules will work with all motherboards.  The physical chips that are on the RAM or Memory may be configured differently from manufacturer to manufacturer. 
High Density memory may only work with certain motherboards and not with others. 
If you purchased a 1GB PC3200 memory module for $40-50.00… it is more than likely HIGH DENSITY and will not work with Intel or nVidia Chipsets.  Just because the rating of the memory is PC3200 or PC2700, etc… does not mean it will work with every motherboard.

8) Remove hardware and cables that are not required for the motherboard to post… 
In other words… go back to the basics. 
All that is required for a motherboard to “POST” is a Video Card and Memory.
If some jumpers from your hard drives or a card is not working correctly… this may interfere with the motherboard posting and cause it to “FREEZE.”

9) Check processor again!!! 
Did you just install a new processor???  If so… put the old processor in and see if the motherboard posts.  If it does… maybe your motherboard requires a BIOS UPDATE in order for the processor to be detected!  If you have the latest BIOS, then maybe the NEW processor is bad OR maybe it is NOT COMPATIBLE with your motherboard.