No Applications showing in ubuntu18.04. Evn search is not working too

I have ubuntu 18.04 installed on my dell 7559 and I have reinstalled it too but still when I click on show Applications its empty. Even Search is not working too. Whenever I search for something it shows searching forever. It sometimes work if restarted but same problem after sometime. Here are some screenshots:

Device: Dell 7559
Distro: Ubuntu 18.04 x64
Kernel: #25-Ubuntu SMP Wed May 23 18:02:16 UTC 2018
Theme: Nebulossa with Flat remix dark miami

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If you after support, please visit where you’ll find a number of Ubuntu Support options.

Ok thanks. You can delete this thread.