Can't reset PRAM on white MacBook 2008

So, I just posted a question about Kittendaddy's problems with his external HD here: http://discussions.apple.com/thread.jspa?threadID=2567440&tstart=0

I was reading some other similar topics and saw resetting the PRAM as a possible solution. So I figured I'd try it.

Except when I hold down Command-Option-P-R when starting up his MacBook, +nothing happens+. It boots up just like always. I tried several times, and it's always the same result. I held down the buttons before I heard the chime, after I heard the chime, before I saw the grey screen, after I saw the grey screen, etc. etc.. I reset the PMU, and I don't know what else to do. It's a white MacBook (2008) running the latest version of Snow Leopard.

Does anyone know what's wrong??

Thanks in advance!