1) Delete the programme folder from the drive you installed it to.

2) To remove the program entry from the Windows Start Menu:

Open the "Taskbar..." entry from the "Settings" slot on the Start Menu.
Click on the "Start Menu Programs" tab then click on the "Remove..." button.
Scroll down the list and highlight the "Graphics Workshop Professional" entry.
Click on the "Remove" button and confirm by clicking on the "Yes" button to remove the program entry.