My PC is in a room, but my TV set is in ANOTHER room, around 10-15 meters distant (considering a cable "swirling" around the house...). How can I connect my PC to the TV set (DVDR, Sat receiver and so on), without too much signal quality loss? What's best between cable and AV sender? Can I have a 720x576@25fps quality with such connections?
Your best option is to run cables. There are some wireless AV sender/receiver units, but quality degrades over distance rapidly, and I doubt you'd be happy at 10 metres, yet they work extremely well up to about 5 metres.