The easiest way to remove manually the agent on Windows is by stopping and remove service and deleting its files and folder.
open a new Command window as Administrator and execute follow commands:
sc stop DWAgent
sc delete DWAgent
Remove DWAgent folder:
c:\Program Files\DWAgent
Open regedit and remove key:
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\DWAgent
Remove DWAgent entry from Windows menus