Mother Board / RAM Compatibility Question ...

I have a system that looks like it needs a new board. I can't get it to boot up even when putting in a new hard drive. During boot, when it's analyzing the drives, it displays the dvd burner drives in an unknown text as you would see corrupted files. Anyway, if you have anything on that ... that could work also. So, I'm looking to replace the board. It currently has a P4 2.8 in it which I believe is good. So, I'm looking to get a board to support that. I only want to change the board. The RAM in it currently (and I prefer not changing the RAM) is 1GB (2 512MB sticks, 1 is DDR333 and 1 is DDR266). I also have a 512MB Stick that's DDR400. The DDR333 & the DDR266 where working together ... stepped down to the DDR266. Anyway, my question is, these new boards are advertising that they will work on Dual Channel DDR2 533/667. Are these boards backwards compatible? Will they work with slower RAM? You're help is greatly appreciated!
:major

 

DDR and DDR2 are actually two different technologies and therefor count as two different kinds of memory. Not only do they handle data in different ways, that little notch in the memory module is in a different spot on the DDR compared to the DDR2. In other words, these two are not interchangeable.

Like gas and diesel, they make look similar, but if your car was made to run on one of them, you can't use the other. You need to buy a motherboard that has DDR memory slots.