Debian 8 (Jessie) - Laptop stops working after closing the laptop lid

To disable the Lid Switch:

1. Open the file /etc/systemd/logind.conf as root.

2. Find this: HandleLidSwitch

3. If it's commented, uncomment and change the value to ignore. The line after editing should be:

   HandleLidSwitch=ignore
   

4. Restart computer and your problem should be gone. Or better restart logind service:

   sudo service systemd-logind restart
   

(Source)