My IPhone 3G email stopped working today.

put your iphone on the a/c charger and press and hold the power and home buttons until you see the apple logo come up. it will then
boot up again. if it stops at the logo then you will need to restore the software,
use DFU mode to restore,
How to enter iPhone DFU mode

• Connect the iPhone to your computer and launch iTunes
• Turn the iPhone off (hold down the power button at the top of the iPhone)
• Hold down the sleep/power button and home button together for exactly 10 seconds, then release the power button
• Continue to hold down the Home button until a message appears in iTunes telling you an iPhone in recover mode has been detected

You can unlock an iPhone 3G through remote unlocking method. This method of unlocking is safe simple and affordable. You can get the remote unlocking for an iPhone 3G from www.Classicunlocking.com . Here are the steps for unlocking an iPhone 3G,
1. Wait for to send you an email saying your phone has been activated or remotely unlocked.
2. Install the latest version of iTunes.
3. Make sure your Apple iPhone 3G phone software is updated to the latest version using the iTunes software.
4. Connect your Apple iPhone 3G to iTunes with a NOT ACCEPTED SIM card.
5. Wait until iTunes detects your Apple iPhone 3G.
6. Disconnect your Apple iPhone 3G and reconnect it after 10 seconds.
7. Your Apple iPhone 3G is now unlocked.

You can unlock an iPhone 3G through remote unlocking method. This method of unlocking is safe simple and affordable. You can get the remote unlocking for an iPhone 3G from www.Classicunlocking.com . Here are the steps for unlocking an iPhone 3G,
1. Wait for to send you an email saying your phone has been activated or remotely unlocked.
2. Install the latest version of iTunes.
3. Make sure your Apple iPhone 3G phone software is updated to the latest version using the iTunes software.
4. Connect your Apple iPhone 3G to iTunes with a NOT ACCEPTED SIM card.
5. Wait until iTunes detects your Apple iPhone 3G.
6. Disconnect your Apple iPhone 3G and reconnect it after 10 seconds.
7. Your Apple iPhone 3G is now unlocked.

try online

hello,ensure you are not clicking on the key wrongly,i would advice you put the phone off and on back to see if the problem stops.if it doesn't i would also advice you ensure you close any application you are not making use of.it could also be as a result of accumulated opening of applications. if that does not stop the problem,i would suggest you get the phone flashed by a mobile phone authorized repair engineer around you.
wish you good luck,
take care.

make sure dates and timezones are correct and synched on both computer and iphone.

My problem is quite similar... My iphone works in some parts of delhi and it shows no service for other parts of delhi... If i use idea sim on my iphone, it works absolutely fine... and if i use my airtel sim on any other phone then also things appear ok..

any ideas?

Just put your iphone 3Gs here for sell i will buy it. www.ebay.com

Unfortunately firmware updates and driver updates for IPhones can be fickled on Windows OS, try rollback the firmware/driver update and see if you are still getting the error. If not you may want to research if the IPhone site has a FAQ or Troubleshooting solution for this.

Based on trying a few iPhone cases, I would look for an iPhone case that:   -  doesn't have a cover flap.  Lifting the flap every time you use the phone gets annoying -  prevents skidding.  The iPhone can easily skid off a table; you can lose it or, worse, break it.   -  has a screen cover that doesn't reflect or refract light in awkward ways -  has a screen cover that doesn't get dirty easily.  
Many covers may have these qualities.  One combination I have tried and liked is:   -  the "white gel case" at the AT&T store (about $20) -  the "screen protector tri-pack" also at the AT&T store (about $10)