My computer or itunes doesn't recognize my iphone 4? URGENT?

ITunes nor my computer recognises my iphone 4 when plugged in properly. It doesn't come up as charging on my phone, and I tried it on another laptop and it works fine, so it's not the wire. I need to sync my iPhone, and don't know what to do, I asked this question before and the advice was uninstall itunes and then install it again, i did this and it still didn't work. It has worked with my iPhone in the past, and now doesn't. I need to sync it in the next hour… Thank you!

It may not be the chord of your charger, but it might be the USB port, so try and plug it into a different USB port, and if that still doesn't work, try plugging something else into them, to make sure they aren't broken. All I can think of, sorry.

Install the latest iTunes version if you haven't. Try turning off phone fully and turn it on.plug it in. If it doesn't work then go somewhere on top of iTunes and go to authorize your pc.see if that works

Ok now firstly which Os are you using? Becazz it can be de problem, windows 7 is more responsive than other older Os's. So apparently it might be your computer developed Driver problem, for de iphone, try to uninstall de Usb controllers from Device Manager in Windows, and click de refresh button for all of dem to reinstall again after dat, if it doesn't work still, uninstall itunes and plugin your iphone and see if it will make a connection sound, if it doesn't, just try and plug other devices in de same port u plugged your iphone if de device works fine then to a conclusion the problem is from your iphone drivers that are installed in your system, get revouninstaller and use it to uninstall itunes and select advanced for it to delete registery traces and errors, after dat restart your pc, reinstall itunes, restart your pc again and plug in your fone. If it still continue den you have to know that your computer ports are too weak to recognize your fone… Also remember to check batterie advanced properties and look for power surge and turn it off it might help.lest that Change your pc.