Pi Pico Unresponsive

I am having trouble connecting to my Rasp Pi Pico and I was wondering if anyone had a solution. Details below:

So first I installed MicroPython as per https://www.raspberrypi.org/documentation/rp2040/getting-started/#getting-started-with-micropython
Tells me to do.

Then I changed the interpreter (in Thonny) to MicroPython (Raspberry Pi Pico), copied some code from the example project I am following (to test the board out) and it worked perfectly.

Then I was able to power this off a USB cable without plugging it into a PC and it worked well. Then I tried to change the code I had copied in and it did not pick up the board (I have tried on three different computers with high quality micro-USB cables which I have tested for working data cables).

And now the board no longer completes any tasks from the old code, and I am unable to connect to it.

It does not show up near C drive so I cannot access the files on it and I have not been able to get any response from it in Thonny (or seen in my device manager in a Com port).

Does anyone have any ideas on how I can fix it?