Hi check your WLAN device, build in into your notebook, I guess. Check if it support n-mode, if so, check how to enable the n-mode, if required. Maybee older wireless hardware in older notebooks may not support n-draft.
i-pod didn't either.
Check on the Advanced Page setting of your wireless mode:
Select Mixed n/g/b
Select Band Width 20/40 MHz (Auto)
Hope that helps
Tom