device discovery question before doing a motherboard upgrade.

[water modem <lundby@ameritech.net>]

I have given up searching the Debian sites and Google and usenet groups 
for the answer to a simple question.
If I want to upgrade a Sarge 2.6 install to a new motherboard without 
re-installing Debian....

What do I run before or after the hardware upgrade to force device 
discovery to be repeated?

I want to do it right without getting in trouble and just can't find any 
information on the process.

Thanks
Walter Lundby