Did you manually enter the speed of the ram though? 1066Mhz is not a default for any motherboard, and the maximum default will be 800Mhz, any faster ram you have to enable a X.M.P. or something similar, or enter the settings manually, including the speed either with the FSB:DRAM or by typing in a frequency depending on the BIOS.
If you set it all correctly, you should be able to boot. If it still says 800Mhz, it may have become unstable and failed post (such as if the startup took very long and heard some clicking sounds before a display would appear). Try updating the BIOS, and if you manage to boot at 1066Mhz run memtest to make sure it is stable.