I don't have a Windows 98 machine to confirm that it's the same (it may not be) but in Windows XP, navigate to the "C:\Windows\Installer" folder. Within the folder, you will see a whole bunch of files with the .msi file extension.. Hovering your mouse over each of the files, (or right click on the file, choose "Properties") will give you information about the program that was originally installed by that file. You'll have to search for a while but frequently you'll find the .msi file which pertains to the problem program. If you can find the correct.msi file for the problem programs, double click on the file and it should start the uninstaller program.. It normally gives you the option to "repair" or "remove".
Hope this helps.
Running: Win98SE, IE6; also WinXPSP2, IE7
On two different computers, I have a number of old, fairly large, no longer used programs that do not have Uninstall options and cannot be found in Add/Remove. I'm told that if I just use Delete, their code will still be left behind. How do I get rid of these programs and free up the space?