cellular network 'option' has completely disappeared!

Hi there,

I have a Dell Latitude that was working well up until this morning. I had been using the cellular network connection (intermittently) over the last month or so and this morning, for no apparent reason, the laptop no longer even recognises there is a SIM card there.

The cellular network option has completely disappeared, as if there is no SIM card in there (however there is).
Please advise how this issue can be rectified ASAP. I note that I have removed and re-inserted the sim card and restarted the laptop which had zero effect.