Salut,
Effectivement j’avais pas lu le post principal… 
J’ai maintenant une connexion filaire qui fonctionne.
Lors de l’installation, j’ai eu un message du genre "un matériel a besoin d’un microprogramme"
Je pense que c’est ce microprogramme que je dois télécharger et installer mais je ne sais pas comment faire… 
voici le resultat de lspci
00:00.0 Host bridge: Intel Corporation 3rd Gen Core processor DRAM Controller (rev 09)
00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09)
00:14.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB xHCI Host Controller (rev 04)
00:16.0 Communication controller: Intel Corporation 7 Series/C210 Series Chipset Family MEI Controller #1 (rev 04)
00:1a.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #2 (rev 04)
00:1b.0 Audio device: Intel Corporation 7 Series/C210 Series Chipset Family High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 1 (rev c4)
00:1c.2 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 3 (rev c4)
00:1c.3 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 4 (rev c4)
00:1c.5 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 6 (rev c4)
00:1d.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation HM76 Express Chipset LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation 7 Series Chipset Family 6-port SATA Controller [AHCI mode] (rev 04)
02:00.0 System peripheral: JMicron Technology Corp. SD/MMC Host Controller (rev 30)
02:00.2 SD Host controller: JMicron Technology Corp. Standard SD Host Controller (rev 30)
02:00.3 System peripheral: JMicron Technology Corp. MS Host Controller (rev 30)
03:00.0 Network controller: Ralink corp. Device 3290
03:00.1 Bluetooth: Ralink corp. Device 3298
04:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 07)
le résultat de uname -a
Linux debian 3.2.0-4-686-pae #1 SMP Debian 3.2.54-2 i686 GNU/Linux
et celui de lsub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 003 Device 002: ID 046d:c077 Logitech, Inc.
Bus 001 Device 003: ID 138a:003d Validity Sensors, Inc.
Bus 001 Device 004: ID 0461:4e1d Primax Electronics, Ltd
merci pour votre aide 