Limewire should not cause your machine to make any unusual noises. If this noise is unique to Limewire (ie it occurs when Limewire is the only application running and at no other time) then something unusual is happening and I would advise you to uninstall and delete everything with "Limew" in the label and then download another copy of the Limewire package. Let me know if that fails to solve the problem and I'll suggest another line of attack.

Gnutella is full of people who either cannot share or make sharing difficult by reducing their bandwidth allocation to the uploading function or the number of upload slots. If you are getting a 10% hit rate, that is very good. I average 5%. You have to be nimble. If there is no response on two requests from a given host, abandon it and move on the the next until you find a live connection.

Chat comes and goes. In theory it works when you have chat enabled in Preferences and you attempt to make contact to those showing the yellow face. It has never worked for me to send although I can receive messages. It is no big loss. The key virtue of Gnutella is the sharing of material. If you want to chat use ICQ, Jabber or one of the other dedicated packages.

A .sit file is a Stuffit file — a compressed document which is not limited as to content and may be unpacked for use on either a Mac or a PC. A .dmg file is one of the formats resulting from the unpacking process and indicates readiness to install.