Besides that I still don't know who your ISP is, the problem of files with many hosts is well know. Those are usually faked files hosted by those who want discourage P2P users from using P2P programs.
Recognizing fake files:
http://www.gnutellaforums.com/showpo...98&postcount=4
That your son can play games with no problem is easily explained. Playing online games and using a P2P program are two completely different issues.
But since you mentioned that you have the 4.12 version of LW, the preference folder would not be " .limewire ", because that was the one from the previous versions (4.10., etc).
Read here on how to delete the folder of your version (Point #2 & 3 in Fixes for Limewire)
http://www.gnutellaforums.com/showth...threadid=36420
Afterwards reboot your computer.
Another point of interest would be whether you have installed any new security software (or any update of your present one) prior to the drop of speed.
In general, by determining what is NOT the cause of your problem, we can get closer to what actually causes your issue.
From my experience, a sudden drop of speed without any prior changes to your computer system usually leaves only the ISP as culprit; believe it or not!
You might want to try to change the listening port. Try one in the range of 49152 - 65535 (eg 64049). Although if this is an ISP issue, there's no guarantee that changing ports will help.
Cheers
