My iPhone won't sync to my computer?

I've tried deleting iTunes and reinstalling it, turning my phone off and back on, turning my computer off and back on and nothing is happening when i plug my phone in?
How do i get my phone to come up on my computer so i can update my apps and evrything?

Can I buy an iphone with bad ESN and connect it with net10? - 1

To avoid paying up to $700 for an iphone in order to pay $50 a month without contract with net10, i'm looking all over ebay and amazon for cheap iphones but mostly all that are new are that price but others say "bad esn" meaning I won't be able to ever connect it with that company it belonged to right? So, if i buy an iphone for 300 or 400 with bad esn from sprint or at&t, can i still flash it and connect it with net10?

How to install ios 4.3 apps on iphone 3g?

Just how can i install ios 4.3 apps on my iphone 3g, which runs ios 4.2.1.
Is there any way that i can force install ios 4.3 on my iphone, or can i install ios 4.3 or even ios 5 apps on my iphone, either force install, or finding an earlier version of the app, in that case can you give a good website of apps earlier versions, for ios 4.2.1.
PS: do actually a step by step, not a Small confusing answer, thanks.

Manually unlocking iphone 4 to a different carrier?

I rescently had my contract terminated because of financial issues and being unable to pay, I've lost service, unable to get it back I want to change to Pay as you Go with a different carrier but I put the new sim in and it just says "No service".

The phone is an Iphone 4, it's jailbroken, and running on IOS6.1.1

I've tried:

-Downloading Ultrasn0w which supposedly unlocks the phone automatically, no luck
-Entering "http://unlockit.co.nz" which allows for manual switch but I either can't figure it out, or it doesn't work
-Resetting network setting

So, I 'am' Jailbroken which must be a plus in solving this, I just hope it's possible, I don't want to buy an entire new phone just to use a different carrier

Also, from reading other sites, they tell you to go to: Settings>Carrier but Carrier isn't in my settings list, nor is it anywhere else, I've looked for quite a while.

Any advice?

Can I block incoming Blocked calls on my iPhone 4?

Spoke with AT&T, my mobile carrier, and the lady had told me there may be a function built into the iPhone 4 or an application I can download that will BLOCK BLOCKED numbers from calling my phone, like you can set a land line up to do.

Why isn't my router working?

For the past two days, all of a sudden my routers being weird. I was using the Internet and then suddenly it's still connected to the router yet I can't connect to the Internet. It's the same for every device I'm on, tablet, iPhone, Xbox, etc… I'm wondering if my routers broken? Or what. I've tried unplugging it several times yet nothing's happened. The send an receive data lights flash on the modem also.

Is jailbreak the same as unlock?

So i recently jailbreaked my iPhone 4 because i wanted to be able to change my SIM card without having to pay £40 to get it unlocked professionally. I understand that i took a risk in doing so but my phone is okay so i'm not that worried. However, when i tried to put in another SIM it either did not recognize it or it didn't work, because i was unable to do anything that required a SIM card. Why is this? Is it because jailbreak doesn't unlock it or is it because of something else?

IPhone 4 stuck on blank white screen?

I opened Safari on my iPhone 4G this morning and nothing loaded, it's stuck on a blank white screen. I can see the black bar at the top that tells me I'm connected to the internet and the battery, but the rest of the screen is plain white. I have the assistive touch dot on because the lock button is jammed, and I can still go into its little menu, but when I press the home button (either on the menu or on my actual phone) nothing happens. I've been trying to turn it off but, again, the lock/power button is jammed, and it hasn't been working. I read that you can hold down "lock screen" in the assistive touch menu, but when I do that nothing happens either. I plugged it into the wall and into iTunes on my computer, still nothing.

When I leave it idle, it's doesn't turn off. The screen gets dark, but it's still on, I guess it's just the back-light that turns off? My only idea is to wait for the battery to die and then charge it and hope it goes back to normal.

Any advice would be much appreciated!