Replacing motherboard and xp activation

I have a ecs k7s5a mb with amd 2400. I like alot of people would like to replace the "quirky" board... I built the machine with xp oem. I know you are allowed so many hardware changes before you have to reactivate xp. I am looking at the msi k7n2 delta so in the future can upgrade my current 2400+. I am sure a clean install is the way to go but will I have to call microsoft or will I still be able to activate online...Thanks in advance.

 

If its been 120 days since last activation, online "should" work.
Otherwise, phone activation will work.

If it doesn't, talk to a live person and explain you simply replaced your motherboard and they will walk you through it.