lost ip address how to get new one

open cmd prompt with admin privs.
type
ipconfig /release
ipconfig /flushdns
ipconfig /renew

this will send your isp a request for an ip address. it only works if your router/modem is working.
note* more often than not you will be assigned your old ip as dhcp distribution can take as many as 5 days to find you a different ip addi. (literally you would have to stay off the net for a week just to get a fresh ip. from some providers)