Are you going to throw the computer away? Format the hard drive. Give it to someone? Remove your profile folder.

Thank you! I'm going to return it, since it's new and faulty.

To safely remove all data stored on the hard drive you will have to perform a secure wipe. Deleting files on NTFS formatted partitions merely sets a deleted flag on files, but don't clear the data on the hard drive, so in theory can easily be recovered with an undelete utility.

• http://www.thefreecountry.com/security/securedelete.shtml

Thank you! If I'm going to Reset Windows anyway in this manner: http://www.asus.com/support/FAQ/1013064/ choosing "Remove Files and clean the drive," would using one of those tools listed in your link be redundant, or would it be better if I did both? Also, which of those tools do you recommend?

As long as clusters that are occupied by a file aren't overwritten then it is always possible to recover such data. Even if you would uninstall and reinstall the Windows OS. Best is to first wipe existing files clean and then wipe the hard drive if you really want to be sure.

Oh wow! Thank you!

OK, that looks like it will remove my OS entirely, and that would void the warranty. Creating a backup copy of Windows externally is beyond me, and I'm also running out of time on the return period.

@cor-el - What I had done was that I imported the profile from my last computer's FF installation. In it, I found backup copies of my bookmarks from five years ago. I wasn't expecting such info to be saved/transferred. This got me worried what other old info might be recoverable by someone who knows more about computers than me.

So... Please tell me this:

1. Does Firefox save passwords (somewhere in the files) that I do NOT tell it to remember? I've always been careful to select "Not Now" or "Never for this site" when it asks me if I want FF to remember passwords on important sites like email, shopping sites, and the like.

2. Also, does FF in some way record/save credit card info, on my computer, when I enter it into a shopping site?

I'm not a techy person, so I don't understand tech terms, but I am very, very worried.

Please help

PS: I ran CCleaner -> Wipe Free space on the drive (the only drive, C) after manually deleting the profile (going into the AppData folder and deleting the contents of the Mozilla folders; because uninstalling FF didn't get rid of it). Would that (running CCleaner -> Wipe Free Space) have helped?

You can wipe only unused space with these programs, but if you want to give/sell the drive to someone else then beware that Microsoft already stores a lot of privacy sensitive data in the registry and in other places, so you would have to reinstall Windows as well any way to remove this data.

Thank you for your response!

1. By "reinstall Windows," do you mean doing so from an external device, after having clean-wiped the drive completely, as with one of the programs you linked above? Because I already reset the system with the built-in utility that can be done through Settings ->Update and Security->Recovery -> Reset this PCS -> Remove Everything, but didn't select "wipe drives" (only selected "Just my files," afraid Windows would be permanently uninstalled if I selected "wipe drives")

2. Would Microsoft have saved this sensitive data on this computer by virtue of me having pasted the old FF profile into this computer, EVEN if I didn't access those shopping sites/entered sensitive passwords/credit cards during the time I have had this computer?

EDIT:

So I guess the question has changed. The original question of "how best to delete" has been answered - by doing a clean wipe. Now the new question is, "How screwed am I with sensitive information, given what I have done?"

What I did was:

1. Buy a new computer; plug in an external HD (that had more files, which I neither copied nor opened) and copied my old FF profile into the new computer. I did this without using any software that may have come in the external HD; I just opened the file folder directly.

2. On that FF profile, while on the *old* computer, I had logged into shopping sites and entered credit card data, but I did NOT log into any of these sites while on the new computer.

3. Sites to where I did log into using the new computer are tied to an email (that I also did log into) that I just use for registering for websites that do NOT require either my real name nor credit card info. I could change those passwords (from a different new computer, when/if I get a replacement), I *think* (as far as I know, given that precaution I took, that I explained in this numeral), with no real damage done, since those accounts don't have either my real name nor credit card info.

4. After deleting the FF profile and all the FF folders I could find under C:/users/[user]/ , with the (I know not great) method of right-click -> delete -> empty recycle bin, I wiped Free Space using CCleaner.

Thanks for bearing with me; I'm really nervous. I know I don't have access to the best solution (the clean wipe of the entire drive), but I don't know how screwed I am given the extent of what I did.

PS: Also, I have not registered this computer with the manufacturer, nor created a Microsoft account at boot/windows registration - I just installed windows without the internet plugged in, so it didn't ask me for a Microsoft account, and it didn't ask me personal questions ... and I left the "register this product" (from the computer manufacturer/McAfee) screen blank.

Best thing to do is what cor-el recommended here: https://support.mozilla.org/en-US/questions/1155384#answer-956963

The only thing safer than that is to install a new hard drive and physically destroy the old / existing hard drive with a large hammer before handing it over to an electronics recycling facility.