Well, the first thing to note is that if the 'E' is showing when you turn it on without the computer on, it is an internal error in the printer, and has nothing to do with the computer. The usual suspects are...
1 - The Cartridges
2 - The Scanner
3 - The Processor
4 - Paper Jam/Out of Paper
First, I would check the cartridges. If you are using OEM carts, take them out and palm them - see if you can feel if they feel light and possibly out of ink (56, 57 and 58s are real easy to tell when they are out, because they are real heavy when they are full - these are HP's only full-load cartridges from that era). If they feel like they should have something in them, the we'll move on to the next stage - MIND YOU - HP Ink Carts will NOT shut down when empty. Even when the fuel gauge on your computer screen says that they are empty, remember that this is only a clock, and that the reading it is giving you is only an estimate.
Take a Q-Tip (cotton swab) and either dip it in water or a grease-cutting cleaner (409 or Fantastik - NO WINDEX) and scrub the contacts (NOT THE PRINT HEADS) and leave them wet - do the same for the contacts INSIDE the printer as well. Reinstall the carts and reset the machine. This should get the carts talking with the printer again, if it is a communication error. If this fails, then new carts may need to be purchased.
IF YOU ARE USING RELOADS (either purchased reloads or having your carts reloaded yourself), you must make sure that the print head is free and clear of clots and gunk. You also need to make sure that the ribbon wire that feeds down from the contacts are not cut or broken (If they are, you may as well toss this cart, as it is dead).
As for either the scanner or processor - there isn't much you can do about these on this machine. When the printer is turned on, the scanning wand should move slightly and possibly blink momentarily. It is best to open the copy lid when turning on the machine to check this. The problem is, even if it doesn't, this does not mean that its bad, since this could also be a processor error. If the problem is either one of these, then you're pretty much out of luck, since these aren't things designed to be fixed by the consumer.
THE SYSTEM TEST - You can get the machine to do a system check, but usually only if it isn't in an 'E' error lock - to do this, you first hold the CANCEL button down, then press the COLOR copy button. It should print a communications and color test at this point, but if you have the dreaded 'E' up, it won't.
PAPER JAM/OUT OF PAPER - Yes, even if you have paper in this machine, the system might still report a jam if you don't check all places. Since this type of printer does not have an anti-kickback stop outside the paper tray/door, you need to be careful when inserting the paper. Turn the power off and pull the paper out of the machine. With a flashlight, look inside and make sure the path is clear. Take the back hatch off at this point, and do this check again. While you have the hatch off, check to make sure that the little wheels on the hatch are seated correctly, and not cockeyed (these printers had a recall because of this). If its okay, check to make sure there isn't any crud built up along the bottom of where the door seats, and then reinstall the hatch. Power her up, and see what happens.
Now, here's a trick you can do that other models in this line can't - you have photo card readers on the front of your machine - these should show up as extra drives on your computer (My Computer). Insert a card that you know has data on it. Check if your computer can see this card and the data (with the printer 'on'). If it sees the data, then there's a good chance that the processor in the printer is working, and that it is a mechanical error (cartidges, scanner, paper feed). If it doesn't... that's not a good sign. MIND YOU, if there was a card in any of these readers durring this time, and you've powered the machine up and down while its still there, well, in the words of the Mythbusters, THERE'S YOUR PROBLEM! You should NOT have a card in the reader while powering up, as this will confuse the processor.
ENOUGH! Try these tests and let us know!
A-N