I am using that flat image of leopard that i downloaded from a torrent, its the only one i could get to work.

for some reason, after i install it, (and everything seems to work, including the internet), once it is rebooted a couple times, the internet no longer works, and when i check network settings, it says nothing is connected to the ethernet. any idea of why this is happening?

It could be any of a hundred things going wrong. There are ways to debug the problem you're seeing. Start reading and ask again when you can provide some details.