The 7 or 8 downloads that have stopped at 40 - 70%...are they showing 'need more sources'? Have you tried doing a new search for the file (sometimes this will kick start a download) or resuming them from the incomplete folder? Were they being downloaded from a single source? If they're rare files & there's only 1 or 2 sources, those sources aren't online for a while...it can be a matter of waiting for them to reappear.

Did the trouble start after changing to a new LW version? Try deleting the preferences folder when LW's properly closed (instructions below)
Fixes for LimeWire

As for your uploads being slow, you're not the only Comcast customer to see this. Some ISPs limit uploads.
http://www.gnutellaforums.com/showpo...7&postcount=11
http://www.gnutellaforums.com/showth...omcast+uploads