Is the DSL light? When you go to Advanced > Status, is the DSL status Connected? And please make sure there is bridge profile in Advanced > Network > Internet page. If yes, then there is nothing need...

Qos can give higher priority for gaming and streaming, for different devices or application, can try this: http://www.tp-link.com/ca/faq-1104.html

If the computer works ok with wifi, the router should be good. Are they connected to 2.4G or 5G? Do you have this issue on both band? You can try change the channel for your wifi. Go to Advanced >...

Unplug the cable from the internet port may not be ERROR level, not very familiar with logs, but it may help if one can find the reason why it fails connection.

The router seems resetting/rebooting itself, if you are using the original power supply, can try other wall sockets. Hold the reset button for 10 seconds and see if there is any change. If not, can...

What is the hardware version? NPT server can only get time from WAN connection, maybe can set it up as router?