Xbox dead, or still to be saved?

I had an Xbox 360 with Jtag, but it didn't work properly and I wasn't shown any avatars. I had read that an update can be done and that would help, only I can't connect my Xbox 360 to the Internet, neither LAN nor Wi-Fi. I wanted to do the update with USB, but the Xbox didn't respond. My brother heard about it and wanted to lend a hand and when I was gone, I completely reset the console, i.e. The hard drive was reset and the system version. Now nothing works anymore, no Kinect and no Internet either. What can you do now? Can you still repair it?

Ne unnecessarily buy either a used xbox 360 or a better one, you can play most games on the xbox one. It is not worth it, actually recommend you to buy a better one directly.