wifi not connecting to dell laptop

Does the system have a shortcut key to enable / disable wifi? If so, press it.

What model Dell is it please?

Is the OS fully updated?

Do you have the latest BIOS?

Thanks

yes i have enable and disable several times
Dell StudioXPS
yes OS is up to date i update anytime i on my laptop
yes i have the latest BIOS

What is the output of:

sudo lshw -C network; lsb_release -a; uname -a; sudo rfkill list

Thanks

*-network
       description: Wireless interface
       product: WiFi Link 5100
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:04:00.0
       logical name: wlp4s0
       version: 00
       serial: 00:22:fb:97:bd:52
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=iwlwifi driverversion=4.4.0-72-generic firmware=8.83.5.1 build 33692 latency=0 link=no multicast=yes wireless=IEEE 802.11abgn
       resources: irq:31 memory:f8000000-f8001fff
  *-network
       description: Ethernet interface
       product: NetLink BCM5784M Gigabit Ethernet PCIe
       vendor: Broadcom Corporation
       physical id: 0
       bus info: pci@0000:08:00.0
       logical name: enp8s0
       version: 10
       serial: 00:22:19:f9:22:05
       capacity: 1Gbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm vpd msi pciexpress bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=tg3 driverversion=3.137 firmware=sb v2.17 latency=0 link=no multicast=yes port=twisted pair
       resources: irq:34 memory:fc000000-fc00ffff
  *-network
       description: Ethernet interface
       physical id: 4
       logical name: enx0c5b8f279a64
       serial: 0c:5b:8f:27:9a:64
       capabilities: ethernet physical
       configuration: broadcast=yes driver=cdc_ether driverversion=22-Aug-2005 firmware=CDC Ethernet Device ip=192.168.8.101 link=yes multicast=yes
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.2 LTS
Release: 16.04
Codename: xenial
Linux polaris 4.4.0-72-generic #93-Ubuntu SMP Fri Mar 31 14:07:41 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
0: phy0: Wireless LAN
 Soft blocked: no
 Hard blocked: no
1: hci0: Bluetooth
 Soft blocked: no
 Hard blocked: no

If you run:

sudo modprobe -r iwlwifi; sleep 3; sudo modprobe iwlwifi

Does it work OK?

thank you for assistance but no luck won't connect

What is the output of:

sudo iwlist scan | egrep -i 'chan|sid'

Thanks

lo Interface doesn't support scanning.

enp8s0 Interface doesn't support scanning.

                    Channel:9
                    Frequency:2.452 GHz (Channel 9)
                    ESSID:"ckLdoor"

Is that your network?

yes, i closed the lid and login again i was able to connect to my wifi but if i off the computer i cant connect on reboot

Thanks

I suggest you report a bug

in case of problems with wifi connection it is recommended to follow https://help.ubuntu.com/community/WirelessTroubleshootingProcedure
for collecting diagnostic information.