Well, close LW completely (i.e. also in the system tray) then press crlt&alt + delete (only once!!). This will open the Task Manager. There you go to the Processes tab and look for any limewire.exe. If you find one (or more) force it (them) to end.
Then close the Task Manager and restart your computer. Then go to the Incomplete folder located somewhere like "C:\Documents and settings\<your computer name>\Incomplete" and check whether said file(s) is in there. If so, open LW and see whether it starts to resume the said file. If it doesn't, go LW>Library>Incomplete and try to resume it manually by clicking on it and then on the "Resume" button.
It can be though that LW will resume the download from 0%.
