Problems with inputting voltage to arduino nano

Hello.

I've been using my arduino nano v3.0 some months now until i ran to this problem.
I had a 9 volt battery plugged between ground pin and vin.

I didnt notice it until i plugged the arduino to my computer via usb cable and i smelled some electronics burning. The pcb under the icsp headers was very hot (i think the voltage regulator).
I disconnected both power sources quickly.
After a few moments of cooling i plugged the arduino back to my computer ( 9 v battery not connected) and my computer or arduino ide didnt recognise the nano.
The power led was lighting up, and after pressing the reset button the led lit up meaning the bootloader is installed.the arduino still ran the sketch. I tried to get the arduino work on other 3 computers and also tested 4 other usb wires. After some time playing around the usb didn't power it on at all. I checked the connections with my multimeter and found out that the + voltege from the arduino end usb was not connected anymore to the voltage regulator.

I took a spare usb wire, removed insulation, cut off every wire exept the positive one and stripped and connected the wire to vin pin on nano. With this fix its working fine, but im looking for something more permanent

I hope some of you could help me :slight_smile: thanks.