Torrent download greatly use up hard disk memory?

[pwnzor]

Hi, i've just installed limewire pro recently, and started downloading a movie using torrent. The movie is 1.5gb and i have 10.8gb in my hard disk. When i started downloading i have 9.2gb left, which seemed alright since thats the amount of space allocated for the movie. But after a few days, the space in my hard disk dropped to 6.2gb, and i havent downloaded anything else or run any other programmes besides limewire(its on a separate computer ;p). I was wondering how could a 1.5gb movie occupy so much space? And the download isnt completed as well..only 50% completed.
Not only that, my computer slow down quite alot too and shutting down or restart takes ages. So i got suspicious n decided to uninstall limewire. But unfortunately after uninstalling, the limewire is still running when i checked at the Windows Task Manager(under processes). I ran a virus scan using AVG anti virus and Norton but found nothing. What on earth is happening? All these happened after using limewire to download the torrent..can anyone help me please?