In which tool your web site had been made? and what kind of updation you required? If you want to add any page or any new menu you want to display on each page of the website then it is necessary that you made your website by using the tool like dreamweaver in which you can mention the editable and no editable area at the time of creation after that you simple have to make changes in template and it will affect on each page.
Yap Obviously it is possible to update your website after it has been published. You just need to download a page in which you want to make changes by using cute ftp or any other ftp server and client software. Make changes in source code and upload it again to your hosting server.
I’ve been to internet surfer past years ago.. and in order to maintain my account safe and good, i will always check it as much as possible, so that i will know some of the development or changes in my account.