Are you using XP or Vista?
Then take a closer look at the "SteadyState" tool from MS.
Link: http://www.microsoft.com/windows/products/winfamily/sharedaccess/default.mspx
Greetz
Then it should work.
> What operating systems does Windows SteadyState work with?
>
> Windows SteadyState works with genuine versions of Microsoft Windows XP with Service pack 2 (SP2) or Service Pack 3 (SP3) installed and Windows Vista supporting Service Pack 1 (SP1). SteadyState works on 32-bit versions for the following operating systems:
>
> * Microsoft Windows XP Professional
> * Microsoft Windows XP Home Edition
> * Microsoft Windows XP Tablet PC Edition
> * Microsoft Windows Vista Ultimate
> * Microsoft Windows Vista Home Premium
> * Microsoft Windows Vista Home Basic
> * Microsoft Windows Vista Business
> * Microsoft Windows Vista Starter
From http://www.microsoft.com/windows/products/winfamily/sharedaccess/faq.mspx
Greetz