NO NETWORK COVERAGE

Hello,
Exactly I don't know from where it's come. Since from yesterday my My Nokia 6681 handset under Reliance net work shows “No Net work Coverage” or “Select ur Network,” I just being fade up tried a lots of way like manually searching, automatic mode applying default code #*7780# But still it’s as it is . Then I format it by using default code (*#7370# ) . I detached my memory card ...but I failed to solve it however my another handset N73 under same network coverage working perfectly .And also my Brother's handset Nokia 6600 working perfectly. Only my one shows me NO NETWORK COVERAGE or SELECT UR NET WORK .Plz help me out from that type of disgusting problem. I can’t accesses internet my mentioned all cells are reliance gprs. RTL WAP. plz help me out plz


jayanta.z@hotmail.com