You need to rid yourself of XP, it does not support MTP properly.
I believe Media Player 9
Media player 11 is the last you can install on XP . Som devices work, but there are severe relibility issues, so Calibre does not allow Calibre to use a problematic function) You are stuck if you want to connect calibre via USB.
A 2 step process might work if the device shows up in Explorer
Save to a Windows (desktop) folder. THEN
Drag and drop into the Kindle folder
(XP is over 12 years old
, we might not like it, but things do move on)