Hi, I recently installed the DJ decompiler on my Win98 system and found that it had REPLACEd the entries in my registry for java files and for class files with its own commandlines. I used the registry editor to restore my settings.
Also the Java JRE installation REPLACEs the jar file registry with its own stuff. Neither install process gave any warning that it was doing this!
If you have used the Windows Explorer: Tools|Folder Options|File Types menuitem to set commandlines for these types of files be sure to backup/export the registry entries for these file types before installing these products.
These registry entries are what are displayed by the Right-click context menu and determine what commandline will be used when the file is openned.