The good thing about a software trial version is that you can always uninstall it if you were unsatisfied with the product. Unfortunately, automatic removal methods often leave registry entries of an application in the system registry. Over time, these obsolete leftover keys can cause your computer to slow down or inflict frequent freezes. You can manually find and delete these registry entries if you know exactly what they are by using the Registry Editor. Otherwise, you should download and install a registry cleaning application that will fix the issue and speed up your PC.
Go to the "Start" menu and click on "Run." (Type "Run" and press "Enter" in Windows 7 and Vista.)
Type "regedit" in the search line, and click on "OK" to start the Registry Editor.
Click on the "Edit" menu option, select "Find," then type the registry entry you are looking for in the search field. Press "Enter" and remove the found item by right-clicking on it and selecting "Delete."
Go to CCleaner website for a free copy of the registry cleaning software. Click on "Save File" in the confirmation pop-up to begin the download.
Double-click the saved set-up file to execute it, and then follow the Installation Wizard's guidelines to install the application to your computer.
Launch CCleaner after the installation is complete.
Click on the "Registry" button in the left pane of the application's window, check the "Registry Integrity" box, and click on the "Scan for Issues" button.
Click on "Fix Selected Issues" when the scan is complete, follow the prompts to back up the registry items marked for removal, and finish the cleanup. Close all the windows and restart your PC.
Use the Registry Editor to back up the registry entries before manual removal. Click on the "File" menu option, select "Export" and navigate to the location on your hard drive where you want to save the backup. Type in the backup file's name, click on "Selected Branch" under "Export Range" and then "Save."
Manual removal of registry entries should be attempted by experienced users only. Beginners or users unfamiliar with the system registry should opt for automatic cleaning instead.