How many ram slot?

[bm23]

i have this motherboard, the Asus P5K (the yellow one, not the black). i was told that it has 4 RAM slots. before i go to buy 2 more RAM, i wanted to make sure that it can work. so i switched the 2 RAM that i have now to the other 2 available RAM slot. in the photo, you can see the 4 RAM slot. originally, my 2 RAM were fitted to the 2 yellow slots. i switched them to the black ones but somehow the computer did not start up. is it because the other 2 RAM slots are meant for different RAM? the RAM im using is 2x1gb corsair CM2X1024-6400.
btw, here is what PCwizard has:
DIMM0 (RAS 0, RAS 1) : 1024 (Double Bank)
DIMM1 : Empty
DIMM2 (RAS 4, RAS 5) : 1024 (Double Bank)
DIMM3 : Empty

 

[Intel_man]

Yes it has 4 RAM slots.

 

[bm23]

any idea why the computer did not boot?

 

[Intel_man]

You have to use the Yellow ones first. The Black ones are only used when you want to expand.

 

[bm23]

oh ok. thanks. didnt know that. . well, i learn something new today