There are a couple of possibilities here.
First, do you have an "Estox" program installed and running on your computer, or maybe you recently uninstalled one. Here's a link that describes that possiblity:
Whether you do or not, you need to make a check for "malware/spyware" on your computer. Click on the links below to download, install and run the free removal tools:
CWShredder Hijack Removal Tool
Ad-Aware 6 Spyware Removal Tool
?Spybot Search & Destroy? Spyware Removal Tool
Hope this helps and let us know how it goes.
I am receiving the message "Windows can't find NBROWSER.EXE This program is needed for opening files of type 'URL: HyperText Transfer Protocol.'" It appears it may have deleted in error or got wiped from the system (Windows 98). Can it be found and reloaded?