Question : Problem: Gigabyte 965P-DS3: runs fine with Pentium 4, no POST with Intel Duo Core E6600

I run the Gigabyte 965P-DS3 board and recently my Intel Duo Core E6300 CPU stopped working. I think the CPU had been fried by heat- I had a fan that was unplugged (gremlins) and the case got hot enough to put colorful heat stress rings the underside of the CPU.  I decided to upgrade to the E6600 but I put in my old backup Pentium 4 Prescott CPU into the system while I ordered the new E6600.  The system runs fine with the old Pentium 4 (but without the performance of the Duo Core naturally).

When I installed my new E6600 the system would not POST. Black Screen, power LED light turning on, CPU fan revolving just about one time, power LED shutting off, cycle then repeated itself until I switched off the PSU.  No error codes or beeps that I heard.  I thought it was a bad chip so I RMAed it for a replacement.  However the replacement CPU, an identical E6600, has the same problem.  Since this has happened twice now, I guess it is not the CPU but something else.  The Pentium 4 still runs the system fine.  Any ideas?

Other specs:
Windows XP
Zalman 550W PSU
ATI Radeon x1950
4 MB GSkill
Antec P180B case
 

Answer : Problem: Gigabyte 965P-DS3: runs fine with Pentium 4, no POST with Intel Duo Core E6600

try clearing the cmos

look in you motherboard manual for the correct jumper