I'm trying to set up a simple ethernet connection between a mac and PC, but it keeps having limited connectivity, and being a PC uses I don't know how to set up the network on a mac. I had it working once but as soon as I turned to computers off it broke and won't work again...

I'm not sure of the direct answer, but something on the following sites may be of help to you. I hope that it is.

Mac Connect - networking Mac and PC (http://www.mac-connect.com/)

Networking with a Windows PC (http://docs.info.apple.com/article.html?artnum=19652)

Apple - Small Business - Mac & PC - Networking (http://www.apple.com/business/mac_pc/networking.html)

MacDevCenter.com -- Connecting Mac OS X to Windows PCs (http://www.macdevcenter.com/pub/a/mac/2002/11/19/mac_pc.html)

MacWindows Tutorials (http://www.macwindows.com/tutorial.html)