Did you lay down rugs or mats? Is the floor making sound- walk around and listen maybe she is bother by this. How old is she? Limit the walking past 11:00 PM. Some people are trying to sleep at these hours. Sex is sex she shouldnt be listening in the first place? Write her a letter make a copy slip it under her door and also give one to the complex manager stating that you never had problems living here and that you are doing the best you can at sloving the problem. Inform her that you dont play loud music and many guest over. Pretty much what you stated in your post. Make it sound as if your willing to work with her, this is up to you. She may have has nasty neighbors before, you never know? Maybe this will clam her down.
I try not walking so much after a certain hour but I do take late night showers and walk to the bathroom. I'm not saying you have sit still when your home but if you like your home and dont want to move, you can work it out. If this doesnt please her than she just plain crazy!!

I don't have specific suggestions to the OP, but I do have a response to hiddeninthemist. I recently wrote a post about my downstairs neighbor complaining about me walking around. I do not think that I should have to "limit" walking around after a certain hour. People who live in apartments do so with the understanding that people are living lives around them. (btw if you read my other post you would see I heavily carpeted and padded the apt. and I walk without shoes inside so it is not that I am inconsiderate.)

Why should walking be limited after 11pm? It doesn't make sense. What are you supposed to do -- levitate -- if you want to get your book from another room, or if you are working on your computer and you need a snack, etc.?? Just because the neighbor goes to bed at 11 means everyone in the building from there on up must go to bed at that time too?

I happen to be a night owl. My downstairs neighbor doesn't like this and has let me know. My *upstairs* neighbors wake up at 6am, a full two hours (at least) before I normally wake up. They walk around above my head and I can hear them (sometimes it wakes me up) if I don't have earplugs in. So -- what do I do? I sleep with earplugs in!! Which is exactly what any apartment dweller should do if they are trying to sleep and someone's footsteps from above are bothering them.

Yes, I read your post "Seneca" and there was a reason I didnt leave a comment beacause I dont agree with you. If you want to walk up and down your apartment all hours of the night, run, skip or jump, I could care less. If you want to live your life and not worry about others then why are you here. YOU should care less what other people think "LIVE" and forget about your neighbor downstair. I think in your original post you stated she was an elderly woman. Come on, would it hurt you that much to be considerate that maybe she is trying to sleep. I'm guessing it would.
There are people who actually go to work in the morning not all but some. After a long day people usually go to bed around 11:30 PM not all but some, Now usually people like peace and quite not all but some, for some people sleeping requires some effort not all but some, Some people might get this not all but some!
I wrote to the OP simply because I felt she hasnt done anything wrong to really annoy the neighbor below and maybe it was just a night issue.
To the OP talk to your landlord about ending your lease because of the issue your having. He/she may understand. If he really wants you to leave I dont think he/she will have anything negative to say when your lease ends. Dont worry about it.

the big thing about "limiting walking aorund' would be that, if you're up after 11, and your bedroom is directly above theirs, go out of the bedroom. Don't pace around the bedroom, or watch the TV in the bedroom if it bleeds through, etc. Don't do your craft project in the bedroom; take it to the dining room after hours. But to not get out of bed to go to the bathroom, or adjust the clock radio, or to not walk gently around the bedroom getting dressed for bed--that's too much.

My new downstairs neighbor works a shift that ends late, so he sleeps much later than we do. I walk softly in the morning, and I leave the bedroom quickly. (Of course, I'm just getting dressed, etc., but I make an extr effort to be quiet in the bedroom)

Also, maybe what's going on is that you are SO quiet, that when you do make noise, she really notices it. That happened to us. We didn't vaccum for literally months. Like, 4 months. We were just never home, or when we were, we were either eating dinner, or our toddler was sleeping & we didn't want to wake her.

Then, when we finally DID vacuum, the guy below went nuts banging on the ceiling.

And, we were on the receiving end of that. For years we had an elderly, not particularly mobile woman living above us. Then, she went into the hospital and died. And for about a year, there was NO ONE above us. Then, the sister who inherited put the apt. on the market, and vacuumed 2 or 3 times a week. Wow, was it loud! Of course, we were intelligent enough to realize that the problem was US and our skewed expectations.

But I wonder if that's it--you're out a lot, so when you ARE home, it seems really loud to her.

As for what your landlord will say to others, well, ask them. If I were them, I'd be hesitant to say something that made it hard for you to get a new apartment--that would be definite grounds for a libel suit. Perhaps they could argue that they're being factual, bcs there ARE noise complaints; but them passing the info on indicates that they've endorsed the complaint, which they haven't.

What shoes are you wearing in the apartment? Some shoes cause a lot more noise than others. I had a neighbor that I swear wore wooden clogs. Very noisy.

Ignore Downstairs Woman and make it known to your landlord that you won't stand for them telling any prospective future landlords that you've had 'noise complaints,' since those complaints weren't reasonable.

Anyone can have noise complaints, after all.

And as far as not walking around after 11pm, what the heck do people who work the night shift do? Are they supposed to live in the basement or something? People need to chill and deal.

hiddeninthemist-- did you READ my post? The WHOLE reason I am here is that I am so considerate in all aspects of my life that it is driving me crazy that I am bothering someone by the mere step of my foot. If you read my post you would see that I tried everything I could to stop the noise for her. After she approached me, I was TIPTOEING around in the bedroom and every step I took I was picturing her sleeping below me.

Well guess what, that is NOT HEALTHY for me to be paranoid about every step. So take your judgments elsewhere. I came here for help (as an extremely considerate person) and your 'help' is not appreciated.

If you didnt like my reply then why address me in the first place)
Im confused, is this your OP? I guess the "HELP" you receive from your OP wasnt enough so thats how you ended up here.
If you know its late at night and she is trying to sleep tiptoeing or walking softly wouldnt be an issue if your trying to be considerate. Uh, does the lady work the NIGHT SHIFT? Did I say you couldnt walk past 11:00 PM?
Seneca, I'm sure you are a very NICE woman. You have to figure out what type of outcome do you want from all of this? You lay down rug mats etc but the lady still has an issue and by the way Ive also lay down rug in my new apartment and am surprise how sound still passes through. I can give you all the advice in the world but at the end your going to have to decide whats bests for you. Do you like your home? Why dont you find an area in the apartment where you wont be directly over her head at night. Try to set it up where everyting is in hands reach - meaning when you know its getting late try to prepare- this is clearly up to you. You can also try talking with her explaining you did indeed install carpet and such and the problem is within the building structure. Asks where does she sleep in which room, just like you are willing to work with her she should also be willing to work with you. Go have a polite converstion with her if you want- if not forget that she even exists.