Arduino Builder – utility for viewing, building and uploading Arduino sketch

Hello, I really like your software.
I have a dell 6400 inspiron laptop and a acer aspire one netbook both with windows 7 installed.
Arduino Builder works great with the dell and the main window of the software displays always 2 com port to be selected for hex upload.
I can easily upload hex files on my feather 32u (selecting leonardo board) through the dell.
With the Acer I have only 1 com port and always the "no new port found" error.
Could you please help me understand why this happens ?
Thanks
Dom