Why does my iPhone constantly say No Service

So i had an old iphone (the first one that came out) and when my partner recently upgraded to an iphone 5 he gave me his iphone 4 which was in perfect order when he gave it to me. So i put my sim in it and it says "No Service" it says this for about 23.5 hrs a day.occasionally i get 1 bar of service and all my msgs come flooding in. So i take it into optus and they give me a new sim card in case its faulty and discover i'm running it on really old software and they recommend i update that. So i did, and i restored factory settings, and i tried resetting the phone, taking the sim in and out, resetting network setting and a whole lot of stuff google, apple and optus have told me to do. No luck. WHY? Also optus said if it doesn't help restoring and upgrading everything, then i should get in touch with apple as it is still covered under warranty. But i can't help but think it has little to do with the handset itself since it works fine with my partners sim in it.

Which iphone 5 case should I get? - 2

I asked another question not too long ago about what cases are the best for the iphone 5. I've narrowed down my options for what I like, but I can't make a decision. Money isn't really an issue, but I want to be smart with my money. The cases that I like are the Trident Kraken, Lifeproof, & Lunatik TikTak 5. I plan on keeping my iphone for at least 3.5-4 years. My current phone now is a tank, I drop it all the time and it just gets scratches. I can be clumsy, and in my work place I need to have something tough and durable. Price isn't an issue. I'm looking for what is going to keep my phone safest for a long time. What do you think is going to provide the best protection?

I dropped my iPhone 4 now speakers are fuzzy

I accidentally dropped it in gravey while I was cooking but I took it out as soon as it fell in. It was super hot and I quickly wiped it off with napkins I had a crappy flimsy case of it that's the only protection I have at the moment but now when I turn my speakers all the way up they sound all fuzzy. I go to sleep with music on but not loud at all. I don't know if that could be a problem but what can I do? I don't have insurance

~ iphone not detecting my Wi-Fi?

I have an active Wi-Fi connection at home. All phones, blu-ray, DirecTV, computer and Apple TV box ditect the Wi-Fi and as of today my iphone did as well. Now, it does not.

It does however detect surrounding Wi-Fi.

I want to use my own though.

I have reset the network settings, reboot my phone and I have reset the router. Any other suggestions you can help me with will be awesome.

iphone 5.

Can you activate Verizon iPhone 5 on another carrier?

I recently bought the iPhone 5 under contract with Verizon but my mother disabled my phone and kicked me out so I wanted I know if you could buy on of those no contract sim cards from another carrier and put it in there? Because I really want to be ale to still use it:/