Filling Forms in Windows

Forms are filled in at various stages in various sites.
Generally the information requested are the 1st name,
last name, user name, email address and so on.
In the attempt to fill in a cage or box, when the first
key is typed the full information fr that particular cage
or box comes on in bolded characters and when clicked
fills the cage or box.
The poped up suggestion comes on with correct version
of the information and the erroneous ones as well.
In case the user has made a mistake earlier, that too
is faithfully presented.
Is there a way to delete the wrongful ones or delete
them altogether once and for all ?
In some sites they are not accepted and thereby cause
confusion and not helpful at all.
All in all they are annoying than being helpful.
thanks,
ben