help to set up my modem pls???

hi every one

i just find a strange things on seting up my internet connection, i have 2 modem, that i use one at the time.

one of my modem that i havent connected for a 2 months, i tryed last night, and when i go to command promt, type ipconfig /all i get the IP adress, the Subbnet Mask, DNS server, also the Gate away number, so it show that i have all the connection set up, i click on internet icon and i have no internet set up??? any idea??? i ask my networking lecture 2day and he said is the MAC address of the modem, but idont think so coz i have a MAC adress when i search,

could any one help me with this topic please???

regard