Hello Customer and thanks for choosing the JustAnswer.com Printers and Office subcategory of the Electronics category.

• Check your hard drive for soft errors.

---

• Turn off the unit in the usual way with the shutdown menu.
• Unplug the power cord from the wall outlet.
• Since this is a unibody, disconnecting the battery may be too difficult.
• Wait 20 minutes before re-applying power.

-----

• Re-apply power and boot-up using the installation DVD if possible to use the Disk Utility.
• Check the amount of free disk space available to rule out memory paging delays due to insufficient memory or page memory disk space.

-----

-----

• If you don't have the system CD/DVD:
• Open Applications.
• Open Utilities.
• Run Disk Utility.
• Select your startup drive and click Verify Disk.
• Select your startup drive and click Verify Permissions.
• If there are problems, try to do both repair options.
• Wait for the repair to complete.
• Reboot.

-----

If you have the system CD/DVD (best option):

1. Start from your Mac OS X Install disc: Insert the installation disc, then restart the computer while holding the option key.
2. When your computer finishes starting up from the disc, choose Disk Utility from the Installer
   Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Disk Utility. menu. (In Mac OS X 10.4 or later, you must select your language first.)
3. Click the First Aid tab.
4. Click the disclosure triangle to the left of the hard drive icon to display the names of your hard disk volumes and partitions.
5. Select your Mac OS X volume.
6. Click Repair. Disk Utility checks and repairs the disk.

Tip: Always start up your computer from an Install or Restore disc when using Disk Utility to verify or repair your startup volume. Otherwise, you might see some disk error messages.

----- ----- -----

• Try downloading and installing the hp drivers again.

----- ----- -----

• Lets start with a USB connection.
• Add a new printer with a similar name, the original file is corrupted and may be on a bad part of the hard drive.

-----

• In the print dialog, click the down arrow to add a printer.

Or

• In the system preferences, click the fax and printer icon
• At the bottom will be a + and -.
• Click the + to add a printer.

-----

• This will give you two printer settings pointing to the same printer.
• After you get the second one working, you can delete the original to avoid confusion

OK

• Click on the apple menu and select about this mac, then look at the system configuration to check the hardware.

• In the hardware, check the USB section you should see the mouse and any other USB devices listed with status.
• If the external drive or printer is not there, the device's USB port or the USB cable may be damaged.
• Even without drivers, it will detect an unknown USB device (external drive or printer) that is connected.