Install a simple Linux distribution such as Ubuntu to start with.
1)There a a few bittorrent clients to choose from. I use ktorrent because it works with KDE.
2)There a few media players to choose from: xine,xmms, noatun, etc. You'll need to setup the soundcard with the alsaconf commandline- easier than it seems- if your distribution doesn't do it automatically.
3) That's a compatibility issue and you'll have to ask that question on a forum dedicated to the distribution that you choose.
4) Quite easy. You have a few programs- k3b, barsero- which allow this. You'll need to add unofficial software sources and do a little configuring. The direction will- again- be on the forum of the distribution you choose to install.
5) See number 3.
6) If it is a card, then there are drivers. If you are talking about a station or an application. You'll have to ask on the forum of- You guessed it!- the distribution of your choosing.
7) Easy. Do you have a connection? You first need to see if there is a native driver for the card. If not, you will need to find the directions on how to use the ndiswrapper.
This transition is quite easy. It's a different system. be open minded and don't be afraid to ask questions. Be sure to research what you will need before you install. The difficulty lays in the amount of challenge you will make it and your determination to overcome. It won't be cut and dry, this is why I gave you the previous advice of searching beforehand. The other options- if you want an open source solution- are NetBSD and FreeBSD; but, these are for people who are willing to learn a more complex UNIX type of system.
Research everything. See about wireless card support. What internet station are you listening to?
If it is a flash or java based application, then you only need to follow the directions for installing flash and java onto the browser you are using and go to that website.