It's probably there. Start by re-searching your Recycle Bin --sometimes if you have a lot of files there, you can miss it. If you find it, right-click on it and click on Restore.
If it's not there, go to (classic) Search>All Files and Folders>type in the file name of the document or words that are in the document into the appropriate boxes>specify to search in My Computer>Advanced>search in hidden files and folders.
If that doesn't work, do the same as above but type in *.doc in the All or Part of the File Name box.
If that doesn't work, do the same as above, but type in *.wbk (this is the extension for Word back-up files),
If that doesn't work, try the same as above, but type in *.asd (this is the file extension for AutoRecover files).
If that doesn't work, do the same as above, but type in *.tmp (this is the extension for Temporary Files).
If that doesn't work, try the same as above, but type in ~. (this is the extension for hard-to-find temporary files).
If those don't work, I guess you'll have to start typing!
I think there are programs you can buy to recover lost data, but I've never tried them.
It sounds like you might have accidentally highlighted the text of your manuscript when you were fiddling with the headers, and accidentally deleted it. Can you try hitting the "undo" button in MS Word?
I got a computer trojan about a month ago that hid most files on my C: drive. They were still there but just hidden. It took me a while to get them back. The trojan was named "Windows Recovery." I ended up using Malwarebytes to recover most of the files.
Now I make backups on a flash drive at least every day.
if your most recent files modified across the board are from yesterday then it sounds like a screw-up with your computer's internal clock: it thinks it's yesterday today, ergo you haven't modified your file yet. I did something similar many moons ago. start by checking the date/time settings on the computer.
I think it has to do with making the headers. After I added the headers and saved the document and closed it, that's when it disappeared. Someone suggested that I undo the last change, but I couldn't access the document to undo anything.
I walked away from the computer for about an hour, and then I realized that searching in the programs field (and I see somebody suggested that too) I did find the document. It still had the same name and when I opened it, it didn't look corrupt and all the edits I had made were properly saved. I quickly re-saved-it-as a new word doc (windows 7) and immediately emailed myself a copy of it and now I'm printing out all the pages to have a hard copy of every edit I've made since the last hard copy which was about 4 thousand words ago. I'm also going to save it on a thumb drive.
I get so caught up in writing I don't have enough sense to stop and be practical I guess.
At any rate, I'm still scratching my head trying to wonder why it relocated. I still don't know where it went, only that I can find it when I do a program and files search. The new copy I made is sitting in today's edits and is behaving normally so far.
I'm looking for a logical explanation for why it happened when maybe there isn't one. But I'm just happy that I found my document.
I shudder to think that I picked up some kind of virus as someone mentioned. I don't think that happened, but maybe I'm just not clever enough to know.
At any rate, I am very grateful to all of you for taking the time to try to help me.