Black screen 'the phone is black screen when it's on. It shows nothing on the screen, I can't see any incoming calls and tests!

Just Unplug the Power Supply and replug it in after 5 minutes, That should be able to fix the issue.

that modem could be bad

I would check with sprint to see if your account is up to date. Otherwise, I would suggest going to your settings and see if you can update your phones's prl and profile. go to settings, tap "About phone", Tap "System updates", then tap each option. Good Luck!

First back up you phone on to your computer or one of the cloud services. Go to the Google Play store and search for backup and find a backup service that you would like and perform a factory reset on your phone if this doesn't work then your speaker is not working and then you might as well replace it.

Have you reported the problem to your network provider

If you do not pay your bill, you will not get incoming calls or messages and you cannot call or send messages. Your phone will not work if you do ot pay for it.
According to the article, and other information I've been reading, there is more than one possible mode a GPRS/EDGE phone network can be configured to operate in, 001 and 002 being the most common. In mode 001 if an incoming call occurs during data use the data session will be terminated and the call will come through. In mode 002, the call will go straight to voicemail. Apparently the majority of 2G networks in the world use mode 002!

It's possible to use the iPhone's field test mode to see what Network Operating Mode is for the network - to do this, first disable 3G, then go into field test mode by dialing *3001#12345#* from the phone app keypad then pressing call, then go to GSM Cell Environment -> GPRS Information, and scroll down to "Network Operating Mode".

I've checked this for all 5 networks and in all cases (at least where I live) it was mode 002 - the mode which doesn't allow for incoming calls when 2G data is in use.

The ramifications of all this are that any time you use data on GPRS/EDGE you will miss incoming calls and unless you have a missed call service with your provider, you won't even know you missed them, as they will not show up on the phone. (And the missed call texts themselves will be delayed as well)

Not only can this be caused by actively using an app such as safari, (or leaving a data using app active with the screen locked) but background mail checks and push notifications will cause it as well. So if your phone is lying there unattended and it happens to do it's 30 minute (or whatever) mail check just before someone tries to call you - missed call.

Having push notifications enabled is even worse, because it tries to keep an active data session as much as possible, and re-establishes this connection every time the data connection is interrupted.

One good example of this is if you have push notifications active, try making or receiving a call, hang up, and call the phone back in less than 30 seconds or so of the previous call - missed call.

The reason is that the GPRS/EDGE connection was interrupted by the first call, so when the call ended the phone immediately tries to re-establish the push data connection, and on a slow connection this takes up to a minute to do and then go idle before the phone can receive another incoming call.

I'm stunned that a problem of this magnitude (which is not really the phones fault at all, but is made far worse by turning on push notifications and background email checking) has been seemingly covered up and glossed over for so long - the O2 UK forum has a message thread with over 500 people complaining of frequent missed calls, with no official acknowledgement from O2 on what the cause is, with the only suggestion being to turn off push notifications. (Which will ease the problem but won't cure it)

What baffles me is why the networks don't just run in mode 001, which allows incoming calls to interrupt the data session - surely an incoming call is more important than finishing downloading an email ? Surely with more and more phones relying on data and trying to hold persistent push connections open, this is only going to become more and more of an issue ?

Perhaps someone like Planner could comment on why networks might not be using mode 001, I'm assuming it either has some drawbacks or compatibility problems with some phones, or is an added cost to support. Is there any likelyhood of this ever changing ?

Now it makes sense why if you're using a network where you tend to get 3G most of the time (such as I do with Orange or 3) then the problem is minor because you're not on 2G very often, but if you're on a network where you will be using GPRS/EDGE a lot (cough, O2) then you really can't afford to leave push notifications enabled, unless you like missed calls...

Force restart it by pressing and holding both the POWER and the HOME buttons for around 5 to 10 seconds until you see the apple logo.

For more iPhone / iPod touch tips like jailbreaking and unlocking, click here.

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if incoming & outgoing is ok then change the disply.
if no incoming or outgoing then go for flashing

In your main menu go to SETTINGS --> PHONE SETTINGS --> VOICE COMMANDS --> CALL ALERT and select RING ONLY

Good look ! =)

You need to update the software/firmware of your phone. Doing this usually solves the problem. if it doesn't then you need a new screen.