I read a lot about advise to change passwords, but have not seen exactly how to do this. I`m sure others like myself would appreciate your instructions. TIA
You don't sign into IE with Virgin Media, you sign into Virgin Media with IE, just like you sign into any other secure website.
I don't have a Virgin Media account myself but, typically, there will probably be an area of the site where you manage your own profile / account details etc - this is almost certainly where you can change your password...
I don't use Virgin Media so I'm not aware of where the 'password change' option is - usually it's in account settings (on a tab along the top, left, bottom or right).