************openqtp.vbs************
Save this  in a vbscript:-
Set App = CreateObject("QuickTest.Application")
App.Launch
App.Visible=True
**************
and in command prompt
Run this
csript openqtp.vbs
****************

I am not sure if you are looking for the same
because to invoke qtp application wehave to use the above 
script 
and for running a vb script in vbs , we use csript/wscript

create vbscript file as:

set app=createobject("quicktest.application")
app.launch
app.visible=true


Then run this file in cmd prompt by its name

Hi

The above given Answers are absolutely currect But 
according to the Question the answer should be without 
using Vb Script

It is possible to invoke QTP or any Application without 
using VBscript by simply Run it's complete path

Ex:

Start -> Run -> 

"C:\Program Files\Mercury Interactive\QuickTest 
Professional\bin\QTPro.exe"

Thank you