rundll32

I just discovered I've got two instances of runll32 running (task list). I'm reasonably sure that the second instance appeared because I've got the nVidia Desktop Manager running in the systray so I'm not too worried about that. No internet on this comp so I'm not worried about viri/trojans. OS is Win 98se. Gonna' go dual-boot with XP as soon as my memory gets delivered and this won't be an issue there.

I know I need this file for WIN98. I'm not going to delete it, obviously. I do however, have the startup option: "Run rundll32 as an application". This box is currently checked, accounting for the first instance.

Do I need to run this as an app? Any advantages, disadvantages in disabling this option?