Install one module to the kernel?
 

I have "forgot" to activate the SB! Live sound card module in my 2.6.2 kernel.

What's the easiest way to install it?

Did you build the module? If not go into your configuration, add it, and type make again. It'll only build the new stuff (won't rebuild things that haven't changed). If you built the module but just aren't loading it add modprobe emu10k1 to your init scripts somewhere. Or add emu10k1 to your module autoload file if you have one.