Sounds more like an isp issue. Really!
Can you answer these questions for us System details - help us to help you (click on link) ... (sorry some repeat details.)

Xtra questions:
(a) Also, try downlding a magnet link from here & tell us what happens re: connecting & speeds, etc. http://www.magnetmix.com/video.shtml

(b) How many files are you sharing?
(c) Go to your incomplete folder & see how many incomplete files are in this folder. A quick way to access it is by going to LW's Library window, select incomplete folder at the bottom & press the Explore button. This will open the folder for you.