Upgrade - Pentium D to Core2Duo

Hi, i'm sort of a noob about upgrades and stuff, plz help~~

I bought a comp about 4 yrs ago and it came with a pentium D processor.
I did some research and learned about different sockets and everything
and then found out core2duo used the same lga775 socket.

I was thinking that's all I needed and bought a core2duo processor and
popped it in...and the computer won't even power on T.T

so~ here is my question..

Do I need a new mother board?

or is there a way to download or update some software to make it work?

Thx