Good Morning Skippytvr,
A warm welcome to the eForum!
It is strange that you would have no signal in all of these places. It sounds quite possible that the SIM just isn't connecting to the network and needs a bit of help!
Can you take the SIM out of your modem and put it in a handset? Once it's switched on this should update the SIM on the network but just to make sure, connect to the Internet on the handset as welll. All you need to do then is put the SIM back in your modem.
Let me know how you get on,
Kay
eForum Team