Well you don't need to remove the value to disable it you just need to set it to 0
Code:
Dim $NoSuggest
$NoSuggest=WriteValue('HKCU\Software\Microsoft\Office\11.0\Outlook\Preferences','ShowAutoSug',0,REG_DWORD)
If you want to remove the value then this will work
Code:
Dim $RemoveSuggest
$RemoveSuggest=DelValue('HKCU\Software\Microsoft\Office\11.0\Outlook\Preferences','ShowAutoSug')
