A clean un-install will remove every trace of the Philips SpeechExec Pro software from your computer.  Below are the instructions for performing a clean removal. 
It is VERY IMPORTANT that you back up your computer before performing a clean uninstall.  You will be working in your registry, do not attempt unless you are an experienced computer technician.
Here is a checklist for a clean un-install to make sure everything has been removed:
1. Close any open Philips Speech applications

2. Go to Control Panel -> Add/Remove Programs and uninstall all listed SpeechExec products

3. Delete theC:Documents and Settings\Local SettingsTempspeechexec” folder

4. Delete theC:Documents and Settings\Local SettingsTempSpeechExecTempAttachments”
5. Delete theC:Documents and Settings\Application DataPhilips Speech” folder
6. Delete theC:Document and Settings\My Documentsspeechexec” folder
7. Remove in the registry following folders
HKEY_CURRENT_USER SoftwarePhilips Speech Processing Dictation Systems
HKEY_CURRENT_USERControl PanelPhilips Speech

8. Delete all other registry keys containing theSpeechExec” string
9. Go toC:Windowsassembly” and delete all the PSP.dlls and PIA.dlls

10. Go toC:Program FilesCommon FilesPhilips Speech SharedComponents” and delete SmEXAudio.dll

11. If there is aSpeechExec” subfolder located in the above mentioned path, then delete it as well.

12. Delete theC:Documents and Settings\Local SettingsApplication DataPhilips Speech”
folder. This folder exists for all SpeechExec versions before V4.2
13. Delete the filesC:Windowssystem32SpeechExecLic.dll” andSpeechExecLic.dat” . These files do NOT
exist in SpeechExec 5.0.
14. Remove all related shortcuts on the Desktop

15. Remove theC:Program FilesPhilips Speech” folder

16. If theC:Windowssystem32″ folder contains following filesSpeechExecSpcapi.dll” and
“SpeechExecSpcapi.ini” please remove them.

Verification Source: Jackie Warren, Philips Product Manager