Nokia 8210 signal fault......HELP!!

Can anyone advise me on the following:
I recently bought a second hand 8210 with a decent signal. Shorlty after I was sent a logo via SMS the signal and logo started disappearing, then returning at no particular time or place. I' ve bought a new ariel with no joy, in fact I'm struggling to get any signal at any time now. I'm with Orange and know very little about mobile phones, so apologies now for any furure ignorance.
I'm not saying the logo had anything to do wth the signal loss it's just that it seemed to disappear shortly after.
I use it as a phone only, no data cable.....too technical!!??:confused:
Trichy