You may want to make sure the router is set to WPA(2) – AES only as per the article below.
Data rate will not exceed 54 Mbps when WEP or TKIP encryption is configured
I hope this helps.
Thanks Joe for the quick reply...
Yes, my encryption is WPA2-AES as I stated, my other computer works great on 802.11n so I strongly believe that it is NOT a router setting, security or otherwise. I even removed all security from the router and disabled my antivirus and firewall without any change. I may be wrong and I will be glad to eat my words if it is a router setting!!!
By-the-way the router is a Linksys WNDR4500.
We suggest you to verify with the router manufacturer the encryption is not mixed, like TKIP+AES but AES only. Otherwise you may contact the computer manufacturer for further assistance since it appears you have discarded other software related possible causes.
I don't know exactly what the problem was but it was a router issue with my Linksys WNDR4500. All the settings were correct, even security Wpa2-AES. After returning to the current firmware from a beta due to an unrelated issue, it seems that resetting to defaults didnt work, even though they showed up as the default setting!!!! Pretty wierd. I was finally able to get the correct default settings by ... holding a paperclip in the reset hole for 30 seconds and continue holding it in, unplug the router for another 30 seconds, while still holding in the reset, plug in the router for 20 seconds, then release the reset button. So all is fine and the adapter is running at 250-270-300.
Thanks for your time!