For the stuation 1, renew the IP throught the DHCP will regain the IP address.
For the situation 2, reboot the route will correct the problem.
Since the DHCP server from the ISP caches the MAC address for each DHCP request, a renew of DHCP request always gets the same IP address for the same hwarware.
This is the bug of the software and I have the similar experiance with both the Linksys router and NetworkEveryway (which is bought by Linksys now) routers, although the Linksys router will hang once every couple of weeks and the other one hangs every other day.
For the situation 2, reboot the route will correct the problem.
Since the DHCP server from the ISP caches the MAC address for each DHCP request, a renew of DHCP request always gets the same IP address for the same hwarware.
This is the bug of the software and I have the similar experiance with both the Linksys router and NetworkEveryway (which is bought by Linksys now) routers, although the Linksys router will hang once every couple of weeks and the other one hangs every other day.