What's the firmware version of your W8968 V2? Download and upgrade the latest firmware. http://www.tp-link.com/en/download/TD-W8968_V2.html#Firmware When connection drops, what's the status of 3G on...

There are two computers? One works OK but another one doesn't? Another one works with a different modem router? Did you try different ethernet cables to connect that computer and W9980? Since Wi-Fi...

Can you try the SIM card on your phone and test if it works in Spain for free? What's the connection status of web interface of M7350? http://www.tp-link.com/en/faq-794.html

Is it possible for you to connect the music system to your home hub directly and test if the network can see its components? You may have to change IP settings on the music system with the new router.

Download the MAC utility from the link as below. It works for PA8010P as well. No worries. :) http://www.tp-link.com/en/download/TL-PA6010_V1.html#Utility

You'd better try different web browers and different computers. If there is anti-virus software running on your PC, disabled it as well.