Protein Explorer will be unable to start if your browser is configured to block it from opening a new window. (Protein Explorer needs to open several new windows in order to work.)

To fix this, please give Protein Explorer permission to open new windows.

Why to you have this problem? The usual reason for this problem is use of software designed to stop websites from "popping-up" new windows to display advertisements. Such ad-blocking software may need to be disabled in order to use Protein Explorer, or it may have an option to give permission to certain websites to open new windows. In the latter case, if you are using Protein Explorer from, for example,, give permission for all websites in the domain to pop open new windows.

Netscape 4.8 does not have a built-in blocker for pop-up windows, but Internet Explorer 6.0 SP2 (on Windows XP) does have! Other generic software that we know about that can block popup windows includes AdSubtract, the Google Toolbar, PopSwat, Popup Dummy, PopUp Stopper, StopZilla, and many more!

How do you find the blocking software? If you don't know what software is blocking popups, here are some ideas to help you find it.

Good luck! If you have suggestions for improving this page, please email them to yours truly.