Desktop Wireless and Networking

Hello everyone.  I hope someone here can help.

A friend of mine recently purchased a HP Pavilion.  I think it's a Pavilion 23 to be exact.  I know the model: 23-q113w.  It came with a wireless mouse and keyboard which currently do not work.  We are trying to resolve the issue soon as it has a 30 day refund on it from whever it was purchased from.  Without a problem resolution we'll have to send the unit back so they can get the refund.

I have double checked all batteries to make sure they are fresh and working as well as ensure they are installed correctly.  Neither the keyboard or mouse have a connect button on them.  The only thing I see on either item is an on/off switch on the bottom of the mouse.  This switch is of course on.

Other than the devices not working, I am not seeing much which can help.  I will say when the unit is first powered on, during the post process a keyboard error of some sort comes up on the screen.  The system doesn't pause during this though; it continues to finish the post process and the OS boots up. 

Thankfully, the touch screen on this works fine so we can use the unit with it if so desired.  The user wants to use the mouse and keyboard.

I have looked on HP's website but I am unable to find anything useful to help resolve this.  As part of my search, I did look at this: http://support.hp.com/us-en/document/c00006821 .  This document proved unhelpful in resolving the issue.

The frustrating part of this is the lack of documenation for the specific model of Pavilion.  One thing which bugs me is I cannot tell where the receiver the mouse and keyboard work with is located at (I don't think either of these are bluetooth based). 

Typically with such wireless devices, it is my experience they come with a USB receiver.  The user is expected to plug this receiver into a USB port.  I cannot find such a receiver anywhere with the unit and its packaging.  Reviewing HPs website, it appears some Pavilions have this receiver built into them.  I cannot tell from HP's website or the included documenation with the Pavilion if the receiver is a seperate, physical USB based item or if the receiver is built into the unit somewhere.

Can someone tell me how to determine if the receiver is built into the unit or if it is seperate?  Or, perhaps someone here knows?

Beyond the above question, any idea how to resolve this?