You will have to first login back to Windows Vista in case you forget your login password. Follow the steps as mentioned in this article and solve the problem.
One of the major problems in Windows is logging onto your PC when you have forgotten your password. Vista allows us to create a “password reset” disk if you forget your login password.
You can just press Ctrl + Alt + Delete > Change a Password > Create a Password Reset Disk. Follow the step-by-step wizard and you’re all set.
1. Click on Start Pearl and type this in the Search bar: control.exe /name Microsoft.UserAccounts
Classic Control Panel View: Start > Control Panel > User Accounts
2. Normal Control Panel View: Start > Control Panel > User and Family Safety > User Accounts
3. Click on Create a Password Reset Disk on the left panel.
4. Click Next.
You will be asked to choose where you want your password key disk saved. I recommend you choose a form of removable media such as a floppy or a USB disk. Make sure the selected disk is still in the drive, then enter your current user account password.
5. Click Next and let Windows do its thing!
6. Use windows password key 8.0
it not only supports XP, 2000, and NT, I have personally tested it with Vista Home Premium and Ultimate. It creates a password recovery CD/DVD,USB Flash Drive for home, business and enterprise. It works perfectly to reset your Windows password. You can download it from http://www.lostwindowspassword.com
Using a Windows Password Key 8.0 bootable CD/DVD to reset windows password
Step1: Choose the existing windows password key 8.0 image file.
You can click "Browse" to browse Windows Password Key 8.0 image file. The file is usually located as the default
Step2: Choose your CD/DVD drive:
Select "CD/DVD" and specify the CD burning drive from the pull-down list. Insert a blank CD/DVD disk into the CD-ROM drive.
Click "Burn" button.
Step3: The burning process starts.
Windows Password Key extracts the ISO image and copies the necessary files on a CD.