There is a program that requires me to logon to the Administrator account for its first run. But the administrator account is nowhere to be found in Windows Vista. How do I logon to my Administrator account? Thanks!

In Windows Vista, you do not have access to the Admin Account by default. When logging into Windows Vista, you do not have the option of using this account.

From the Start menu:
1. right-click on Computer and choose Manage.
2. expand Local Users and Groups
3. select the Users folder.
4. Right-click on the Administrator login and choose properties.
5. Clear the Account is Disabled checkbox and you have now enabled your Administrator account.

but do not see the Local Users and Groups under Manage. by the way, I'm using windows vista home basic.

If you use Vista Home, you need to enable it through Command Prompt. Note that here autologon is optional:

1. Logon as the account you created during the installation.
2. From the Start menu, go to "All Programs", "Accessories"
3. Right-click on "Command Prompt" and choose "Run as Administrator"
4. Click "Allow" from the ConsentUI prompt
5. In the resulting Command window, enter "regedit" and press enter
6. In regedit, browse to HKLMSoftwareMicrosoftWindows NTCurrentVersionWinlogon
7. In the Winlogon key, create a new value of type REG_SZ (string) _title_d AutoAdminLogon and set the value to 1.
8. Also create a string value _title_d "DefaultPassword" and set it to the password you want for the Administrator account.
9. In the value "DefaultDomainName" enter the name of your computer
10. In the value "DefaultUserName" enter "Administrator"
11. Close regedit
12. Back in the command prompt, enter "Net User Administrator password* /active" (replace password with the password you entered for DefaultPassword).
13. Log off or reboot. You are now logged on with the local Administrator account. To stop it from auto logging on, remove that "AutoAdminLogon" value or set it to 0.

Good luck!

I have the same problem, I tried the things you suggested, however it says 'Access Denied.' in command prompt when trying to edit winlogon. Have the same access denied message if I go through the registry editor. Solution?

At step 3 make sure you choose "Run As Administrator"

...3. Right-click on "Command Prompt" and choose "Run as Administrator"