Windows unable detect Arduino UNO R3

Hi, so for a number of months I have been using my Arduino and everything has been fine. But today I was uploading a program (using a motor shield and external power supply) and it worked fine last night and for about an hour today, then I went to upload another program and it would no longer detect the device. I have checked all the COM ports and I know it is not the cable as I can connect my friends mega just fine. The “L heart beat” still works and as far as I am aware that means my bootloader is still working but the computer no longer makes the sound when I plug it in or out anymore.

Any ideas on what might be going wrong?
Time is of the essence for me and any help will be greatly appreciated.

Edit: I have done many hours of googling and this is the last resort and It does not work on both windows 7 or 10.

"the computer no longer makes the sound when I plug it in or out"

Signal cable failed? They don't last forever. It''s just wire and flexes a lot.

@saldrock, please do not cross-post. Do not hijack. Other post removed.