Just installed a Coolermaster Aero 7+ on my Athlon XP2400 on Abit KD7-G. However when I press the power button it starts up for about half a second then shuts down. Is this an indicator that the CPU core isn't making proper contact with the H/S, or is it likely to be something else?
Check in the BIOS to see if there is some kind of 'cpu fan failure' prevention method enabled. The Aero 7 has adjustable fan speed, and at its slower speeds, most BIOSes assume the fan is about to fail (or assume that it isnt working at all) and shut the computer down as a precaution (to protect the processor from overheating). I had the same problem the first time i used my Zalman flower cooler with its slow spinning 92mm fan. This option will usually be situated on the page where you can observe voltages/temps, etc. Disable the option, save changes and then reboot - hopefully all will now be well. Let us know if it isn't.... Good luck
Board doesnt boot could indicate a short somewhere, either that or the fan fail as suggested. To test this whack a higher cfm fan on the CPU fan header. If it boots then you need to turn off fan fail. If not then theres another issue somewhere... Check for shorts, and that the PSU is ok.
I had the same problem with an Abit NF7-S, so I guess this will apply. It was just a simple case of re-seating the CPU and heatsink.