HELP my G700 no more sees GSM networks only 3g

Hi all, i just got a G700, been using it for about a month and all had been cool, until some days ago after it accidentally fell to the floor, i restarted it and observed it searched for a longer time than usual for the network service, then it saw it, after a while it stated ' emergency calls only" this see-sawed back and forth for a while until it only displayed the emergency calls menu. I then took out the SIM put in my K800 and there was a full network service(meaning the network side is ok) put it back in my g700 and the same problem.. i then tried another networks sim(this network offers 3g service) and all was well. Now i have discovered that even with this new network sim card,if i attempt a new search for mobile networks while in GSM mode only, it says no network coverage, if i turn it to dual or 3g only it recognizes only the network i talked about (with 3g services), to be more exact i put in a third sim altogether from another GSM only network and the same emergency calls only... my primary no is on the GSM only network. I wrote to SE support and they havent replied yet. I cant afford to send it back to the vendor( i bought it from a retailer online)..Its a customized Hk cda 1207-8402-R18A model, i used SEUS and was told my software was up to date, i opted to reinstall it all the same. after that it still doesnt see gsm networks..once in a while it will then it goes off and even says no network available(when in fact there is) right now im on 3g only and its working well, with another sim in it. any assistance will be really appreciated. tnx

it may be loosed antenna connector, you said it fell on the floor right? you are giving your phone a hard impact, so, it's better that you check the antenna connector and the antenna

Thanks alot, that makes a lot of sense..now checking the antenna, is it something only sony ericsson techies can do? is it something i can do myself or any phone technician? i for one dont even know where the antenna is (in this model) any ideas. tnx a million

Thanks alot, that makes a lot of sense..now checking the antenna, is it something only sony ericsson techies can do? is it something i can do myself or any phone technician? i for one dont even know where the antenna is (in this model) any ideas. tnx a million

any mobile phone repairer could do that

Thanks alot rider.. will do that and report how it goes.:)