I forgot to say that the two old ram is double face and the two new ram is single face this is the only different but all the ram is Kingston ddr2 800mhz, Is that's why it's not working ?
Not sure what revision your motherboard is but you may be correct. I just lifted this from the Rev2.0 manual:
Due to chipset limitation, read the following guidelines before installing the memory in Dual Channel mode.
1. Dual Channel mode cannot be enabled if only one DDR2 memory module is installed.
2. When enabling Dual Channel mode with two or four memory modules, it is recommended that
memory of the same capacity, brand, speed, and chips be used and installed according to the
configurations in the first table for optimum performance.
3.
Because of chipset limitations, do not populate both DIMM sockets of the same channel
(e.g. DDR2_1 and DDR2_2) with double-sided memory modules to prevent system's failure to
start or incorrect detection of memory modules.