NodeMcu v3 - No connection to COM port after flashing firmware

Hello, I got a NodeMcu v3 today and wanted to try it out straight away. So I took the NODEMCU FIRMWARE PROGRAMMER, plugged the board into USB, held down the FLASH button and clicked RST. I continued holding down the FLASH, the COM port was displayed in the program, so I set baud 9600 and clicked flash. I released the FLASH button on the board, and the program continued to load the soft. It seems to have loaded nicely, but when I plug it into USB now the computer does not display the COM port. Only when I hold down FLASH, click RST and let go of FLASH does it display the COM port, I connect to it at 9600 and get nothing. When I click RST then I get some rubbish. ESPlorer can't connect to the board either. I'll add that I've flash the board using 9600, 230400, 115200 speed, same thing every time, it doesn't throw any error.

I hope I have clearly explained what I was doing one by one.
Thank you all in advance for your help and suggestions as to why it doesn't work.

1. the VCOM port is not related to the ESP8266 programming, so it should always be visible - check, as you probably don't notice it.
2. the "rubbish" after reset - this is a boot code message transmitted at 74880, so everything is fine.
3. be careful what you programmed the chip with. If with a program from 2015 - then don't be surprised that it doesn't necessarily work. I recommend a careful reading of https://nodemcu.readthedocs.io/en/master/en/flash/

BlueDraco wrote:

1. The VCOM port is not related to the programming of the ESP8266, so it should always be visible - check, as you probably don't notice it.

.

Well I check in the device manager. And when I just plug it in like that, there's nothing. Only when I press FLASH click RST and release FLASH is it visible. When I now click RST then after a few seconds the port disappears again.

I think there is a problem here somewhere....

Added after 2 [minutes]: .

After changing to 74880 actually, I get something:

.

Added after 17 [minutes]:

BlueDraco wrote:

3. Be careful what you programmed the chip with. If with a program from 2015 - then don't be surprised that it doesn't necessarily work. I recommend a careful reading of https://nodemcu.readthedocs.io/en/master/en/flash/

.

I've tried this esptool.py, only when I type into the console what they've written there, it pops up that Windows can't open the file.

Added after 3 [hours] 1 [minutes]: .

Ok, I read that python needs to be installed.
I type this in:

esptool.py --port COM7 write_flash -fm dio 0x00000 nodemcu-master-21-modules-2017-12-29-14-50-13-float.bin

And it pops up that the application was not started properly.... what am i doing wrong?

There is a ready-made single-cavity .exe for this python tool - it works well and conveniently. Read to the end of the page I've linked.

Regarding:
https://github.com/marcelstoer/nodemcu-pyflasher

It is when I try to launch that I am displayed the same error.... application has not been started properly

Added after 38 [minutes]:

Because I don't see any .exe there except the one from 2015.... And if you can see it could you give a specific link to the exe?

Added at 13 [hours] 29 [minutes]:

I found somewhere on the net another program, from 2014, supposedly flashing ok, at the end it just says failed to leave flash mode.... Well, but in any case the esp8266 is not burnt, because it sends this information via uart, but why doesn't the flash uploaded to it work? And why is it only visible on the computer when in flash mode?
I would appreciate any suggestions.

After a very hard battle I managed to program using this python flasher. But no change, the module works as it worked....