Still mired in the job

I started my new job a few weeks ago, and tried to leave my old one behind. The key word there is "tried," since I'm not very good at letting go. Our HR department found a temp who was looking for something perm, and I did some training, and it seemed fine. She asked what seemed like logical, sensible questions about the processes. She said she had experience with our email program (most people don't have experience with it, so this was a plus,) as well as the basic MS Office stuff. Her personality was pleasant. Things were going reasonably well. Or so I thought. Last week, I got a number of calls for guidance. She was preparing the agenda for the staff meeting, and wanted input regarding how to set it up. I sent her the template and told her to fill it in with the items for discussion that had been sent to her by the staff. She sent it back for me to review. Every single time she added an item, she emailed it to me to ask if it was OK. It was time to do the month-end reports, and she wanted me to walk her through the written procedures for compiling them. She was asking where to find a spreadsheet she needed, since the path emailed to her by the assistant in the other department didn't make sense to her. Since I didn't have the path, and don't have access anymore to look for it, I hopped the shuttle and went to her desk to walk her through it. I showed her all of the stuff she needed (the spreadsheet, the database from which she would pull the other report she needed, where to enter the data so that the charts would generate properly.) She wrote down the network paths so she could find the files again, and said she would contact IT to have some shortcuts set up on her desktop. The next day, she emailed me to ask about the spreadsheet. She was getting a message that it was password protected, and she could not access it except as "read-only," which did her no good, she said. I explained to her how to copy the information she needed from the read-only file, and where to put it in the report. The next day, she contacted me again about the monthly report. She couldn't find the MSAccess database she needed, the one that had the report she needed to run. I led her through the network directory that has the database, but I couldn't remember the exact filename. I led her through opening the files that I thought could be the correct ones, and I described what she should see on the screen. We exhausted every option, but she still could not find the database. So, I hopped in my car to come to her building and see it for myself. Halfway there, my cell phone rang. She was calling to tell me that she had found what she needed- the database was open all along, she just needed to close one screen to see what I was describing. Yesterday, Boss stopped by my desk. "Kaaaren," he said, in that voice he always used when he was going to ask me to do a pain-in-the-ass project or talk to someone contentious that he didn't want to deal with. "The temp. She's...I feel like she's maybe not working out so well. What do you think?" He said she seemed nice enough, but that she just wasn't catching on. He still didn't have the monthly reports, she wasn't doing a good job of scheduling meetings, she was asking questions that he'd already answered for her (after having made notes when he answered the first time. And the second.) "So, I want to...,"he started to say, then stopped. "Well. Go ahead, read my mind." "It's not my job to read your mind anymore." "It's not your job, but we both know you still can." "I never could read your mind. You're just predictable," I said. "You want to get a new temp." "I think it's best. She's not working out, really. She doesn't seem to know the software, so she can't even start to focus on the actual duties. But here's the thing..." he said, a bit sheepishly, "Can you bring someone else up to speed? I'm not going to make a habit of this, I promise, but I could really use your help." The procedures are written down, but it is much easier to understand how to do something when you can see it being done, when you can ask for clarification. Four years ago, when I went to work for Boss, the person who took my place didn't respond well to my attempts to train her- she had written procedures and it wasn't my job anymore, so she wanted me to stay away. But she wasn't following the procedures, and the functions weren't being performed properly, and I was having to sit in meetings listening to people talk about how the procedures must be crap, since so many mistakes were slipping through the cracks. Boss told me that it wasn't my problem. "Did you document your procedures?" he asked. "Yeah, but she's not following them. That's why [x] got messed up, and why Lane's so mad." "Did you offer to show her how to do it?" "Yeah, but she said she had it under control, once I told her why I wrote the procedure the way I did." "Then it's up to her to do it. You can only do so much," he told me. Still, it took me months (strike that, years) to stop worrying about what was happening to "my" job. In fact, in some ways, I may not have ever stopped. I vowed that I wasn't going to do that again. But now, HR has to let this temp go and to get a new one. I avoided having contact with the temp today, since I wasn't sure how it was being handled. I saw Boss at lunch, and he said she wrote him a note saying that she was surprised and disappointed that this happened. And I feel like a jerk for not being able to give her more of a warning that it wasn't working out. And I assumed that the problem was my training, not the temp. So, how can I think that the next one will work any better? And how do I walk away without feeling like I've left a piece of myself behind?