How to fixup broken downloads
 

My machine locked up the other day (due to some other software) and I had to do a hard reboot. Afterwards, Limewire lost track of all in-process downloads. I have not been able to figure out how to make it look at the files and resume downloading them.

this is a normal occurrence when a machine crashes...the programs don't get shut down properly and all data in transition (being written) is lost and the files become corrupted

You would need to downgrade back to LW 4 to resume the incomplete files; see Downgrading to LimeWire 4 from 5 & resuming incomplete downloads :)