So, essentially your wifi is more reliable than your ethernet. Unusual - it's normally the other way around. The fact that it's Hotmail or Tiscali is almost certainly irrelevant - you either have a good internet connection or you haven't.

First - are you sure that your wifi is connecting to your own router and not your neighbour's? Worth checking.

If not that, it might be other ethernet kit, the router itself, the ethernet adapter in your computer, its configuration, or the cable. Unplug any other ethernet equipment and reboot the router. Check that the RJ45 plugs and sockets are clean and secure. Try another cable - older ones may not work well with newer faster equipment. Route it away from mains wiring. Try another socket on the router. Check that you have the latest driver in the computer - if you converted to Win10 you may have a default one. There may be a setting to reduce the speed (Device manager, Network adapter, properties at a guess.)

Failing all that you need another computer or another router to eliminate one or the other.

I'm not going to suggest Linux, but you could try a Linux 'live CD' to test whether you get the same problem as with Windows.