Whenever you remove a program from your computer system, including trial-period programs, traces and components of these programs are left behind in the computer's registry. These registry entries are unnecessary. To ensure that the trial-period program is completely gone, you have to delete the keys and values of the program in the registry. You can do this by using the Microsoft Registry Editor tool.
Click the Windows "Start" menu, and then click "Run."
Type "regedit" into the "Run" text field and click "OK." This will open the Windows Registry Editor.
Click "Edit" in the menu bar and select "Find" in the sub-menu.
Type the trial program name, registry key or value string of the program into "Find What" field in the "Find" prompt and click "Find Next." Also, ensure that the "Keys," "Values" and "Data" options under the "Look At" section are check-marked.
Delete the found entries by right-clicking them and selecting "Delete." Repeat this process for each key or value.