Printers are not always directly compatible from one OS to another. Jumping from WinXP to Win8 is quite a large leap and chances are your scanning features and applications are gone or very different.
The best thing you can do is uninstall and reinstall with the latest full software solution available from http://support.hp.com if one is even available. Review the software that comes with your installation and review the documentation for how to opperate it on your new OS.