Ignore ports for now. Ignore things like MTU values as well. Step 1 is as follows:
1) Uninstall the 3rd-party software that controls the USB adapter.
2) Uninstall the USB adapter from within Device Manager and remove it from the USB port.
4) (Optional but recommended). Run a cleaner such as click here and then navigate to C:\Program Files and delete any folder that has been left behind by said 3rd-party software.
5) Grab the installation CD and insert it but CANCEL IT IF IT RUNS.
6) Plug in the USB adapter and wait. New hardware will be found shortly.
7) You will be asked about drivers; move through the wizard to the option that allows you to choose a location to browse. Choose your CD drive.
8) Setup your network connection again via the WLAN icon in the Notification Area - double-click on it, refresh the list of networks and connect to yours.
Get back to us if that does not improve the situation.