Is this wireless card the original one that came installed in the computer when you bought it, or was it installed later?
If it already came installed, we recommend that you contact Dell first to see if they have any updates that might resolve this issue. Here is a link to Dell* Support Page that might help you as well: Latitude E5540 and E5440 Windows 7 driver install order | Dell US
Thank you for the answer.
Yes, it was bought with the card installed already. It is a genuine w7 and all software's also (corporate pc with administrative rights for me).
Unfortunatelly I already tryed what you suggested. No success...
Some other ideea?
In this moment I use an USB wifi adapter to this purpose...
have you tried to connect to any other network other than these two and see if the same thing happens? You may also try to connect to a public network and see if the same thing happens.
To check with your computer manufacturer would be the best option since the wireless card came already installed and this fits the characteristics of an OEM's (Original Equipment Manufacturer).
The reason we are suggesting this is that being an OEM card, the manufacturer has adapted the card to be compatible with their system and in this particular case, only them are entitled to provide you the correct drivers that might resolve the issue. Please check with them and let us know as you since it connects when you use your phone as an AP.