Does it drop connection while being actively used? Or does it lose connection when going into idle (power saving optoins?)
Does it require a restart afterwards? I have a pc which can be overloaded with network activity and effectively disable the onboard NIC (awesome...). The only solution I have found is a reboot (seems related to high incoming UDP traffic)
Does the main pc have a firewall? I have had a few firewall products enact flood protection and effectively block all traffic from the router.
The only other ideas I have are to try another network card (NIC) and see if the same problems occur.