Can you start the command prompt by right clicking on the icon and selecting Run As Administrator.
At the prompt type cd \ and press enter
then type cd C:\Temp\HP_WebRelease\util and press enter
then type Uninstall_L2.bat and press enter
can you tell me what it says after you type the last command.
This should uninstall all remnants of any HP Device so we can start a new fresh installation from the setup file you downloaded previously.
We'll get there in the end