Unbale to connect wireless printer

Actually i'm trying to help out my cousin sister, for setting up her HP Officejet J4680 all-in-one printer. She wants the printer to work wireless and it should be easy for her to connect with laptop. She is running vista on her laptop and connects to the internet wirelessly, but she is unable to connect her printer by using the USB cable. But the problem is that the printer keeps on creating the following Network report:"Your wireless router requires a WPA security passphrase". It also shows to 'Run' the wireless network setup to re-enter the wireless network WPA security passphrase. For doing that do i have to cancel the existing wireless settings?

Can any one tell me from where do i get the WPA Security passphrase?

It's not safe for the router to leave widely open for the hackers, so WPA protection is given for each an every router. WPA pass phrase is created by the owner at time of installation.

Thank You very much and i'm glad to receive information from you. Anyways i didn't knew about it, because myself i had never use it