Worked for me. Not reboot required.
lechtard...you're using XP i presume? Not sure why it wouldnt work if you are.
This is the code, perhaps you could follow it and do it manually:
'xp_pastitems.vbs - Remove Past Items from the System Tray
'Based on fixes by Doug Knox and Kelly Theriot.
'© Doug Knox and Kelly Theriot - 8/23/2003
Message = "To work correctly, the script will close" & vbCR
Message = Message & "and restart the Windows Explorer shell." & vbCR
Message = Message & "This will not harm your system." & vbCR & vbCR
Message = Message & "Continue?"
X = MsgBox(Message, vbYesNo, "Notice")
If X = 6 Then
On Error Resume Next
Set WshShell = WScript.CreateObject("WScript.Shell")
WshShell.RegDelete "HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\TrayNotify\IconStreams"
WshShell.RegDelete "HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\TrayNotify\PastIconStreams"
Set WshShell = Nothing
On Error GoTo 0
For Each Process in GetObject("winmgmts:"). _
ExecQuery ("select * from Win32_Process where name='explorer.exe'")
Process.terminate(0)
Next
MsgBox "Finished." & vbcr & vbcr & "© Doug Knox and Kelly Theriot", 4096, "Done"
Else
MsgBox "No changes were made to your system." & vbcr & vbcr & "© Doug Knox and Kelly Theriot", 4096, "User Cancelled"
End If