Putting DDR3 in a DDR2 motherboard is like the old "Square peg in a round hole" thing.
It's physically different and won't fit. Trying to make it fit, would certainly Destroy something.
If you really think you need more ram, and you have a 64 bit OS, then here's an option for you.
Go to www(dot)Crucial(dot)com and download their Ram Scanner program.
It will run on your PC and analyze what you already have and then go back to the web site,
where they will tell you what options you have and how much it will cost. If you wish, you
can buy new ram right there and they will mail it to your home, office, etc.
I use this option for my customers, all the time. It's fast, it's handy, and Crucial sells only
the very top quality ram and...