Q: pls help with reset iphone 4s as i am unable to unlock the phone

You have to restore your iPhone by the recovery mode as described in that article you reference, http://support.apple.com/kb/HT1212

Ok,let's backup...what exactly is happening that you cannot unlock the iPhone?  Is this a previously owned iPhone that you just bought?

If it is previously owned, when you try to restore is it asking for the Apple ID and password of the previous owner?  If that is the case, you MUST get that Apple ID and password to unlock the iPhone.  iOS 7 has an Activation Lock feature that is really for anti-theft protection.  That feature cannot be bypassed, not even Apple can help with that.

So, if that is the problem you need to either get the Apple ID and password or get your money back.

When you say it is locked, when you try to restore is it asking for the passcode or for an Apple ID and password?

Do you have an iCloud account?  Did you turn on Find My Phone on the iPhone?

This is a little confusing since you said you just bought the iPhone, then said it is your old iPhone, and then said you just bought today.

So, is the iPhone that is locked your old iPhone, not one you just bought?

Is if locked because you set a passcode and cannot remember the passcode?

Or, is it locked and asking for an Apple ID and password?

Then it sounds like you have a new iPhone that is locked to a cellular service provider...is that correct?

If your iPhone is locked to a particular carrier, you must talk to the carrier to get the iPhone unlocked to use on other carriers.  Apple will not do that unlocking.

If I am not understanding, try again to explain exactly what you mean by locked.