How to peform a clean uninstall of BlackBerry Desktop Software

To remove the BlackBerry Desktop Software, complete the following steps:

1. Close BlackBerry Desktop Manager.
2. Open the Control Panel and double-click Add/Remove Programs.
3. Select BlackBerry Desktop Software and click Change/Remove.
4. On the InstallShield Wizard window, click the Remove option, followed by Next.
5. On the Confirm Uninstall window, click OK.
6. On the InstallShield Wizard window, click Finish.

Follow along, now:

Task 2 - Delete the Research In Motion folders from the registry

To delete the Research In Motion folders, complete the following steps:
Click Start>Run.
Type Regedit, then click OK.
In the Registry Editor, delete the Research In Motion folder located in HKEY_CURRENT_USER\Software\
Delete the Research In Motion folder located in HKEY_LOCAL_MACHINE\Software\
Note: This key will not be present if you are removing BlackBerry Desktop Software 4.0.

Remove the BlackBerry Desktop Software folder under HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Uninstall'

Leave the Registry Editor open to complete the next task.

Task 3 - Delete the Pumatech or Pumatech Technology key from the registry (if present)

Pumatech shared folders only exist in the registry for BlackBerry Desktop Software 4.0.1 and earlier.

To delete the Pumatech and or Puma Technology key folders, complete the following steps:
In the Registry Editor, delete the Puma Technology folder located in HKEY_CURRENT_USER\Software\
Delete the Pumatech key folder located in HKEY_LOCAL_MACHINE\Software\
Close the Registry Editor.

Task 4 - Delete the Research In Motion folders from your hard drive

To delete the Research In Motion folder, complete the procedure that corresponds with the Windows operating system you have installed on your computer.
For Windows 2000 or XP
Open Windows Explorer.
Delete the Research In Motion folder in C:\Program Files\

Delete the Research In Motion folder in C:\Program Files\Common Files (if present).
Delete the Research In Motion folder in C:\Documents and Settings\\Application Data\

Note: If you are unable to see the Application Data folder, it might be a hidden system folder. See the Additional Information section of this article for instructions on how to display hidden files and folders.

If you were running BlackBerry Desktop Software 4.0 Service Pack 1, delete the BlackBerry Desktop folder in C:\Documents and Settings\\Application Data\.

Task 5 - Delete the Pumatech folder from your hard drive (if present)

To delete the Pumatech folder, complete the procedure that corresponds with the desktop software version you have installed on your computer.
If you are running BlackBerry Desktop Software 4.0 Service Pack 1 or later, delete the Pumatech Desktop Setup folder located in C:\Program Files\Research In Motion\
If you are running a version of BlackBerry Desktop Software earlier than 4.0.1, delete the Pumatech Shared folder located in C:\Program Files\Common Files\


Task 6 - Restart the computer

The desktop software should now be fully uninstalled. Restart the computer to make sure that all background processes are cleared from system memory.

Sources: http://www.bbhub.com/2007/01/31/how-to-peform-a-clean-uninstall-of-blackberry-desktop-software/