ethernet networking :cry

hi all was wondering if anyone can help
im tring to create a shared internet connection through an ethernet cable
i can get the connection running but when i turn the host pc off i lose the network and have to create a new network again:cry
im running:
host: windows xp
realtech ethernet adapter
ntl usb cable modem

target: windows xp media
realtech ethernet modem
crossover ethernet cable between both pcs

any help or advice would be appreciated

 

Not really an answer to your question as I don't know why its losing that connection but is there a reason you don't simply go through a router?