Open your guestbook in a new frame
In the so called frameset of your website, you can give each frame a name with the name attribute. How to organize this, depends on the software you use to design your website. Check the manual or help-function of the programm. After you have given the frame, in which you want to open your Write2me guestbook, you need to change the HTML code of your Write2me button like this:target="frame"
Replace frame with the name you gave to the frame. To open the guestbook within a new window, you can add _blank here. To open your guestbook within a full and new window, enter _top to your code. Delete the above mentioned out of your code, when you want to open your guestbook within the same frame.