How to assess if my network card needs replacement?
Solution 1:
The technician mentioned that it could be a problem with the notebook's antenna, not the card. How am I able to verify this by myself?
I have replaced wireless cards on my machines. The only way you can tell is to open the laptop and verify the connections on the card by comparing to the Hardware Maintenance Manual, and that the connections are secure.
Otherwise (8 years old), disable it and try a good quality USB Wireless Card. See how it performs with respect to speed.