Need to disable fn

[Duh]

Hi i need to disable fn key. i have 12.04
specs below .

thanks

product: M285-E ()
vendor: Gateway
version: 3402683R
serial: 0039170453
width: 32 bits
capabilities:
SMBIOS version 2.4,
DMI version 2.4,
SMP specification v1.4,
Symmetric Multi-Processing
configuration:
boot: oem-specific
chassis: portable
cpus: 2
uuid: 0002D319-E51D-B211-8000-8BC0535209A3