The Registry key you mentioned exists in XP, but I'm not sure if it existed in 98. I don't have a 98 machine running at the moment, but this tip from mvps.org might help:

Applications can be removed from the Open With dialog box. There is a list of applications stored in a registry key that are removed from the open with list.
Steps to Remove a Program from the Open With... Dialog Box

• Click Start - Run...
• Type regedit into the Run dialog box
• Navigate to the following key
  HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\explorer\FileAssociation
• In the right hand pane double click the value named KillList
• This will bring up a dialog box with the contents of the KillList. This is a list of applications seperated by semicolans
• Press the End key to place the cursor at the end of the list, type a simi-colon followed by the applications filename and extension.
• This is a sample kill list %1;explorer.exe;dvdplay.exe;mplay32.exe;msohtmed.exe;quikview.exe;rundll32.exe

The only thing i have under that key is "CUTLIST" and there isnt anything in it except

Thanx for looking that up my friend

Hmmm- come to think of it, I'm not sure that Win 9x keeps a separate list of the "Open with..." programs in the Registry. That is, I think the list may be generated dynamically based on Registry information for the individual applications you have installed.

I've seen this tip posted in a few places, but I haven't tried it myself:

* Open Regedit and navigate to HKEY_CLASSES_ROOT\Applications.

* Under that key, locate and hilight the name of one of the programs which you do not want to appear in the "Open with..." list. (The name will be the ".exe" name of the main program's executable file)

* Right-click in the right-hand pane of the Registry Editor and choose New->String Value from the resulting menu.

* Name the new String value NoOpenWith. Leave the Data field of the new string value blank.

* Repeat the above for each program which you want to exclude from the "Open with..." list.

* Reboot the computer.

Here is an example of what im talking about

http://www.uploading.com/files/5KYSG...ument.doc.html (OPENS IN WORD PAD)

Notice the entry "My" in the list (Thats 1 i wanna remove) and theres another one @ the top of the list with nothing in the name field. (Same icon as the one that says "My")

Ah Well.........