Hi,
did you check the startmenu for the program group related to your webMethods installation?
Please check under Services configuration if there are some Messaging related services (i.e. Broker or UM) have been leftover.
If there is nothing visible there, this might mean, that the uninstallation has already been done and it is safe to delete the folder afterwards.
If nothing seems to help, you can try an external uninstallation helper tool, which might be able to clean up leftovers after incomplete uninstallations.
Regards,
Holger
#Integration-Server-and-ESB#webMethods