I need to know what all information a random website can get from my computer, and whether a website can tell which of my two computers on the same router I'm using. I know websites can determine what operating system and browser I'm using and the IP address of my modem, but I'm wondering if there is any machine-specific information that a website could use to tell my desktop from my laptop the first time I visit a website (so no cookies have been downloaded yet).
If I use two different programs (e.g. a web browser and a bit torrent client) could someone tell that those two interactions were the same computer?
If I visit a website once from my desktop and once from my laptop, can the website tell the difference between those two computers?
Along with IP address, port number, and the data being torrented, what does a computer at the other end of a bit torrent connection receive from my computer?