In most cases, whenever a printer won’t pickup paper, it is usually because of the pickup rollers. I would recommend going to hp.com and searching for your specific printer model. Look for the part lists and find the part number for the pickup roller. Note, most printers have at least two trays. One is where you load most of your paper and the other for the manual paper tray. You want to make sure you change the rollers for the tray that is giving you the most problem. You can also verify this to be a problem if you touch the rollers. If they’re really smooth, it won’t grab the paper. Rollers should be almost tacky. Finally, you can try different paper or fanning the paper so that it’s not sticking to one another. Good luck.

Well, it sounds like you have successfully replaced the hard drive, now comes the fun part. You have to install the operating system! :-) You'll need to insert the original DVD for OSX that came with your machine and boot from that. You can also boot from an external drive that has a system bootable partition already installed.

It almost sounds like your hard drive has died. If you can boot to an external, that would (should) confirm it. Based on your description, I don't think is the system / mother board.

Here's how I would handle it. Connect everything to the logic board, EXCEPT the hard drive. Try to turn it on. If the machine tries to boot up but gives you the message that there is not a bootable disk found, then problem is most likely the hard drive. If you still get a black / blank screen, problem most likely the logic board.

If the text messages are important to you, you should consider getting software that can copy them to your computer. After you do that, you can restore as new.