just got a iphone 4, wont restore or update through itunes. my computer isnt detecting the device. I keep getting an error code 2009. please help.

Both of your errors are addressed in this article: Get help with iOS update and restore errors - Apple Support

If I were you, I would try to borrow a geniune Apple cable from someone and try it again.

Could be the USB cable. Did you check this?

Related errors: 13, 14, 1600, 1601, 1602, 1603, 1604, 1611, 1643-1650, 2000, 2001, 2002, 2005, 2006, 2009, 4005, 4013, 4014, or "invalid response."

If the USB connection between your device and computer is interrupted, you might not be able to update or restore.

To narrow down the issue, you can try different equipment:

• Use the USB cable that came with your device, or a different Apple USB cable.
• Plug your cable into a different USB port directly on your computer. Don't plug it into your keyboard.
• Try a different computer.
• Solve other issues with the USB connection, then with your security software.

If you still see the error message, check for hardware issues by following the next section.

Check for hardware issues

Related errors: 1, 3, 11, 12, 13, 14, 16, 20, 21, 23, 26, 27, 28, 29, 34, 35, 36, 37, 40, 1002, 1004, 1011, 1012, 1014, 1667, or 1669.These errors mean that your device or computer might have a hardware issue that stops the update or restore from completing.

1. Check that your security software and settings aren't blocking your device from communicating with the Apple update server.
2. Then try to restore your iOS device two more times while connected with a cable, computer, and network you know are good.
3. Make sure that your security software and settings are allowing communication between your device and update servers.
4. If you still see the error message when you update or restore, contact Apple support.

copied from Resolve iOS update and restore errors

Maybe your antivirus or Windows firewall is blocking the communication between your computer and Apple's servers. But I do think it's your cable.

Before you try to change your security software settings, follow the advice given by AmishCake and see if you can try another USB cable.

Has the phone been erased and only the "Welcome" screen is showing up on the screen? Can you try to set up the phone using your Wi-Fi network?

Clicking on the blue parts in this sentence, for example, will open a link to a help article about this issue, providing you with more detailed info.

Check that your security software and settings aren't blocking your device from communicating with the Apple update server.

See if connecting in recovery mode will make your computer recognize the phone. This is explained in this article:

If you can't update or restore your iOS device