I tried to reset my AirPort Extreme 802.11n by powering down, rest button.
Like this?
Power off the AEBS
Wait a few minutes
Hold in the reset button and keep holding it for an additional 8-10 seconds while you simultaneously plug the power back into the AEBS
Release the reset button after the hold period and allow 25-30 seconds for the AEBS to restart
Temporarily, connect a spare Ethernet cable from your Mac to one of the LAN <-> ports on the AEBS
Open AirPort Utility
DSL is working via ethernet.
Can you provide the make and model number of the DSL modem?
Tried to uninstall airport utility 5.5.3
Confused. Did you drag the application to the Trash? Are you saying that you could not delete the AirPort Utility application?
and revert to old version
Are you saying that you could not download and install AirPort Utility 5.4.2?
AirPort Utility 5.4.2 for Mac
You will probably be prompted to update if you install this version.
I just can't seem to acces the base station and configure the internet connection.
Assuming that a hardware problem is not affecting things....you will be able to get things going.