Hi yosequesi, there are two similarly named profile folders:

• C:\Users\username\AppData\Roaming\Mozilla\Firefox\Profiles - this has all your important data in it

• C:\Users\username\AppData\Local\Mozilla\Firefox\Profiles - this has mostly temporary files you can remove

To bypass your session history and start up clean:

(1) Open your profile folder

For example, type or paste the following into the Windows Run dialog or the system search box and press Enter to launch Windows Explorer:

%APPDATA%\Mozilla\Firefox\Profiles

In that folder, do you see one semi-randomly-named folder? If so, click into it. If you find multiple such folders, find the one that was most recently updated.

(2) Hide sessionstore.js file / remove sessionstore.bak file

In your profile folder, scroll down and look for sessionstore.js -- it's okay if it's not there, after a crash, it usually is missing. If you do find it, right-click > Rename the file with a .txt extension for possible future reference.

Note: By default, Windows hides the .js extension. To ensure that you are looking at the files I mention, you may want to turn off that feature. This article has the steps: http://windows.microsoft.com/en-us/windows/show-hide-file-name-extensions

If you see a file named sessionstore.bak it's probably very old now, you can just delete that file.

(3) Hide the session history backups folder

Find the sessionstore-backups folder (this may be back toward the top of the file list. right-click > Rename the folder to sessionstore-old (or similar name of your choice). You may wish to use files from this folder to get back some of your recent tabs, so please do not delete it.

Now, when you start Firefox, it should be unable to find any previous session history files and will start a new session.

By the way, to escape some scam pages users have reported recently:

(1) Recurring dialog saying you have to call a toll-free number for a password

Try pressing Esc several times quickly in a row to break the reload cycle so you can close that tab.

(2) Large popup with audible voice in the background

Click the OK button to dismiss the dialog. Do not move the page in any way. The dialog should reappear.

The second time, the dialog should have a checkbox along the lines of "Prevent this page from creating additional dialogs". (See attached screenshot.) Check that box and click OK. You can close this tab now.