Netscape Navigator has been discontinued and the manufacturer has declared it's Official End Of Support.
This means that there will be no future product or security updates from the manufacturer. Therefore, you should consider changing to a different browser.
Netscape Toolbar
Netscape's pop-up blocker is integrated into the browser. To disable the pop-up blocker:
From the Edit menu, select the Preferences option. The following window will appear:
Click on the arrow beside the Privacy & Security option on the left-hand side of the window to make it display the options shown above..
Click on the Pop-up Windows option
Remove the checkmark from beside the Block Unrequested Pop-up Windows option
Click OK to close the Window
To re-enable pop-up blocking, check the Block Unrequested Pop-Up Windows option