You broke the old computer... Can you put the old drive in the new computer and boot to it?

I'm not sure how to. I have a rescue back up drive which I can examine by plugging it in at a usb port. Sorry, I'm not at all techy.

The old and new computers... are they both desktops or laptops? What type of hard drive, old or ssd?

Both are laptops. The old laptop can't be opened but I had data rescued from it onto an HDD. My new laptop is SSD.

......

No, both PCs. Old laptop ran Windows 10, new one Windows 11.

Both are laptops. The old laptop can't be opened but I had data rescued from it onto an HDD. My new laptop is SSD.

YEAH!!! Why can't they be opened. What models are they?

Old laptop was a Dell Inspiron. I spilt olive oil over it :( Fatal. But I sent it off to have data rescued from its hard drive.

The new one is an Asus SonicMaster.

So the data rescue folks sent back a working drive right?

They sent back a drive that I can access, yes.

I guess the drive was just data and not one you can boot with.

I think so. I was hoping somehow I could copy across logins.json and key4.db to some useful place.

Do you have another computer? You can also backup your current data on the new computer to your phone.

If you start playing with those files on your new computer you may mess up your current data on the new computer. I would look for another device to backup or sync your current data before moving the old data to the new computer.

Sounds like a good idea. I haven't got so many new passwords as all that, so could save them to a csv file and copy them back manually, but for the rest I'm too tired to attempt anything risky tonight. I'll try and look at it afresh tomorrow. Thank you very much for all your efforts on my behalf.

Good night, but syncing to the phone would be better. IMHO Later

You can copy logins.json and key4.db from the backup top the current profile folder with Firefox closed to transfer the logins.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

You can use the button on the "Help -> More Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page (Root directory).

• Help -> More Troubleshooting Information -> Profile Folder/Directory:
  Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

You can copy certain files with Firefox closed to the current profile folder to transfer or recover personal data.

• bookmarks and history: places.sqlite
• favicons: favicons.sqlite
• bookmark backups: compressed .jsonlz4 JSON backups in the bookmarkbackups folder
• cookies.sqlite for the Cookies
• formhistory.sqlite for saved autocomplete Form Data
• logins.json (encrypted logins;32+) and key4.db (decryption key;58+) for Passwords saved in the Password Manager
  key3.db support ended in 73+; to use key3.db in 58-72, make sure to remove key4.db
• cert9.db (58+) for (intermediate) certificates stored in the Certificate Manager
• persdict.dat for words added to the spell checker dictionary
• permissions.sqlite for Permissions and possibly content-prefs.sqlite for other website specific data (Site Preferences)
• sessionstore.jsonlz4 for open tabs and pinned tabs (see also the sessionstore-backups folder)

I think I've been wrong all along about what I had found where and that I may have lost my passwords forever. Sorry for using up everyone's time on this. I appreciate the efforts.

If you have both logins.json and key4.db in a backup or profile folder and you see encrypted logins if you open logins.json in Firefox tab then you should be able to transfer those logins to a Firefox profile like I wrote above.

• https://developer.mozilla.org/en-US/docs/Tools/JSON_viewer

Firefox uses two locations for the Firefox profile folder. One location for your personal data (e.g. bookmarks) and another location for temporary files like the disk cache, so make sure to look in the correct location.

Location used for the main profile that keeps your personal data (Root Directory on about:profiles).

• C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>

"AppData" is a hidden folder, so you need to make sure you can see hidden files.

Yes I 've been trying that. And I thought I'd found it, but I was wrong because I didn't understand how to do the searches. The backup sevice I used did not copy across the hidden files it turns out. So I may need to ask another computer repairer to have a look for them.