If you have Win98, you should take a look at the autoexec.bat and the config.com in your C: root.
You should also use anothe browser temporally, in order to surf the web correctly and search about msbb.exe.
The last and crappy way is to open the registry, look for all entries containing msbb.exe and deleteing them. Or you can search yourself in your hard disk/s for this file and rename it to msbb.crap, eg.
That should stop it. After rebooting
it and try to find a solution to this specific program on the net.