Another question about my computer.

My other thread was http://sythe.org/showthread.php?t=790294

On the same topic of my Hp Desktop with the Fried Motherboard.
Now that I took everything off that HD, I no longer need it or the whole computer, one big waste.
Can I buy a new Motherboard, swap it out, hook everything up, turn it on and it work?
Do I have to buy a new processor too, or other shit?
What would you do if you were in this situation?

 

Nah the computer isn't that old, it's Hp Pavilion Media Center m7680n.
It had nothing wrong with it at all, wasn't slow in anyway, still worked like the day I bought it brand new.
Until it woke me up beeping loud one night, and it wouldn't turn back on after.
I took it to Best Buy Geek Squad, they verified it the Motherboard was done.
Instead of dealing with the problem then, I said fuck it, and bought the New Asus they had