loosing network conection

Win ME on laptop and desktop. Systems linked via crossover cable and networked using network setup wizard.
The network worked fine. Internet connection sharing also working ok.
problem is after a period of time the network disconects for no apparant reason? This happens about 3 times a day. Restarting the laptop sometimes reconects the network?
Files are visible on the host from the client but if i open one the conection is lost during or just after the file transfer.
Power saving features are turned off on both machines. Any sugestions would be appreciated
Thanks