Now I'm REALLY confused! All week, I've been following a series of steps that were clearly written by someone else. That person knows all of the different things I've tried. I'm not sure if you've been following the thread and you are now offering the next step or if what you suggest is an entirely different way of trying to solve the problem.
As I wrote earlier, my computer shows that I have the PSC 1310 All-In-One series installed and ready. I have been using it successfully for many years now. It prints just fine, and all of the scanner checks I've done say there's nothing wrong with it. The problem is that I get the "internal error" message every time I try to scan something.
It seems you are aware of different software that's specific to the PSC 1315. I've always been told that the 1310 series includes the 1315. I also get regular HP updates, but maybe that's just for my Compaq laptop. If there is specific software for the 1315 all-in-one, that should solve the whole problem!
I think it would be easier to proceed with resolving this problem by staying with the same person, so I don't waste either my time or HP's any more than necessary.
Thank you very much for your suggestions. I hope to hear back from someone who knows the entire history of all the things I've tried so far. Unfortunately, I never get a name, so I have no idea who you or the other person is.