Check to be sure it is enabled in your BIOS.
I usually have mine off, because it causes airport issues when resuming from sleep.
When I needed it at work, I would just enter BIOS and turn it on.
We have wireless now, so I have it disabled.
Mini 9 | OS X 10.6.7 | NBI 20100616212351| BIOS 05 | 32 GB Runcore | 2 GIGS RAM
10V | OS X 10.6.7 | NBI 20100616212351 |BIOS 06|160 GB|1 GIG RAM| 6 Cell Dell Battery
Back up Mini 9| OS X 10.6.7| NBI 20100616212351| BIOS 05 | 32 GB SuperTalent | 2 GIGS RAM