Internet Explorer might not offer to remember your password if you’ve previously declined to store the password by clicking “No” in the prompt, when the auto-complete feature was on. This is because, you opted for No, this keyword “No” is stored as an entry in the Password List. The word ‘No’ or data is stored as a list because you may have more than one username/password pair for a given page.
So, unfortunately, even if you want to reverse the decision and allow IE to save your password, you can’t do so. Here’s what you can try at least. If you succeed you can overcome this limitation and force your browser to remember the password…again!!
Force Internet Explorer to Save Passwords
Run Regedit and navigate to the following key:
See the left pane > select the Storage2 key > Click File > Export > Save the key to a safe location as SavedPassword.reg. You will need it later.
Now in the right pane, select all values & click Delete.
Now in IE, visit the site, whose password you want to save. Fill in your details and then click to submit the data. Now when IE asks if it should remember your password, click Yes.
Come back to the Registry Editor. Click File > Import > Select the file you saved as SavedPassword.reg > Click Open to merge the saved data into the registry.
This way you will also have saved your previously saved passwords as well as the one you just created.
Internet Explorer 10 and later on Windows 8 changes things a bit. In Windows 8 with IE10 and later, IE no longer stores encrypted passwords in the registry; they’re stored in the Credential Manager, which you can find by typing Manage Web Credentials in the Start Screen’s search box; it’ll be in the Settings section. However, this display does not show any of the “No password saved and do not ask” entries.
You can read more on manage passwords in Internet Explorer using Credential Manager.