download problems

I have a list of unfinished downloads. When I start LW only a handful of downloads start. The others are all stalled. When I click on fix stalled they start looking for the file, when they fail it looks for the file. I can find the file on the hard drive but it won't start downloading and it resets the file to zero despite it being partially downloaded. When I do a search I can find the file again but it still refuses to start. I cancel the download and restart the download again. If I close the search window some of the files that are restarted stall. I am using LW 5.5 with XP. I don't think it is my computer because it only started doing this when I upgraded to 5.5 basic.