I don't really know why you are trying to do this. A widows password will be enough to secure your data, especially if your only concern is your mum...
Again, with the BIOS boot password, 8 characters is more than enough in most situations - Although you can bypass these with some tom foolery.
Also... Don't make duplicate threads. It congests the forum. http://www.sevenforums.com/general-d...in-screen.html