Wireless---Wireless Advanced---Enable AP Isolation If the option is unchecked, it means that it has been disabled. Describe the problem with Chromecast in details. Sometimes, to change channel like...

Why a switch should do that? SG1005D is a plug and play device and works like a hub...

You have to figure out ports related to bittorrrent, so that you can add a correct rule. Copied from http://www.imfirewall.com/en/protocols/Bittorrent.htm. Protocol Summary and Ports Range of...

To check if the card has been detected or not, go to Computer Management---Device Manager, can you see it under other devices or network adapters? If not, you'd better try to unplug it and plug it...

Strange issue. Have you tried a different PC? I won't install the program since there is bulit-in utility. http://www.tp-link.com/en/article/?faqid=306

Since other clients are working OK, try to contact Sony and ask for some advice...