Q: restoring iPad

Apparently you have never synced with this computer before. That happens the first time that you connect the device to a new computer. A new computer for this purpose is any computer that the device has never been connected to.

About the 'Trust This Computer' alert on your iPhone, iPad, or iPod touch - Apple Support

If you are not able to restore that way, try erasing with iCloud

Erase your device with iCloud

If you set up Find My iPhone on your iOS device or Mac, you can use iCloud to erase and restore it.

1. From another device, go to icloud.com/find.
2. If prompted, sign in with your Apple ID.
3. Click All Devices at the top of your browser window.
4. Select the device you want to erase.
5. Click Erase [device] to erase your device and its passcode.
6. Now you can either restore from a backup or set up as new.

If your device isn't connected to a Wi-Fi or cellular network, you can't erase it with Find My iPhone.

Dhyana wrote:

I have forgotten the passcode to my iPad 2 & so it is disabled. 

Follow these steps if you've forgotten your passcode:

If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled - Apple Support

Hmmm... I have not "locked" my iPad but it seems to me that if you followed the steps in the article and connected to iTunes that it work. Try it again. If not, take it an Apple Store, they should... 

Make sure you're getting all the way into Recovery Mode using force restart while USB connected to the iTunes computer.

Try Force Restart with the iPad plugged into your computer after it appears as a device in iTunes.