Here's where Intel screwed up.  There is a Core 2 Duo E6600.  There also is a Pentium Dual Core E6600.  The Pentium Dual Core E6600 was launched a couple years after this motherboard was EOL.  Will the PDC E6600 work, I dont know.  Will The C2D E6600 work, most definitely.
 
Confirm which CPU you have and if you have the PDC E6600, then all I can suggest is give it a try.  Based on the spec of this motherboard is should work, but again, being that the CPU was launched so late after the motherboard was EOL, there is no way to know if the microcode to fully support that CPU is in the latest bios flash.