Helping people with computers... one answer at a time.
Windows administrator accounts aren't intended for continual use and can be hard to find. We'll look at logging in as administrator, and alternatives.
I created two accounts on my computer, One Administrator and one limited. My computer does not go to the login screen so I don't get the option to log onto my Administrator account. It automatically goes to the limited account. What can I do to fix this?
As you've surmised, for many reasons "administrator" is special. It's actually considered dangerous to be logged in as administrator all the time since any malware you might encounter would have administrative privileges. As a result, Microsoft has slowly made Administrator just a little harder to access with each version of Windows.
And yet, sometimes you just need to be Administrator.
I'll look at both XP and Vista, and also recommend what you might want to consider instead of logging in as Administrator.
Windows XP Pro
If your machine automatically logs you in as your limited or other non-administrator account, start by logging out. (Start menu, Log Off ... item.) You'll then likely be presented with the login screen, but with only the one non-administrator account, or a list of all accounts except administrator.
Press CTRL+ALT+DEL. Twice.
What you should see is the "old" Windows login dialog box that will allow you to then specify "Administrator" as the login account, and the administrator password.
Windows XP, all variants
Reboot your computer, and as it's booting - towards the end of the BIOS information and before the Windows logo appears, press F8. This will give you the Windows boot options.
Select "Safe mode with networking" and let Windows continue booting.
In Safe Mode, you should be able to login to your administrator account normally. Naturally, you are in safe mode, so other restrictions may be in place. Typically the point of logging in as administrator in safe mode is to do so only temporarily. While logged in as administrator, you can change a problematic system configuration, or perhaps give another login account elevated, or even administrative privileges.
Windows XP: Recommendations
I typically give my Administrator account a strong password, and then never login to it again. Ever. Instead, I give my "normal" login account, the one I use every day, administrative privileges. Yes, that means that I'm running as the equivalent of administrator all the time, and take on all the security risks associated with doing so.
If you can, I do suggest creating and running in a "Limited User Account" - essentially an account that does not have administrative privileges. Whether or not this works for you is highly dependant on exactly what you do on your computer everday. Unfortunately, some software simply assumes or requires that it has administrative access to your machine to work properly.
The ability to login to the administrator account is disabled by default, you simply need to enable it.
Right click on My Computer, and click on Manage. Expand the Local Users and Groups item, and click on Users. Now right click on Administrator, and in the resulting dialog, uncheck Account is disabled. Click OK, Log out, and Administrator should appear on your login screen.
Important: if you plan to leave the administrator account enabled, log into it and set a strong password.
Windows Vista: Recommendation
What I see people wanting to do is login to the real administrative account because they're tired of being prompted for confirmation, or the administrator password, every time something needs administrative access. If you really need to go that far, logging into the real administrator account is probably the wrong solution: giving you login account administrative privileges, and then turning off UAC is. That gets you back to the same level of security that you had back in Windows XP without having to login directly as administrator.
And I recommend leaving the Administrator account disabled.
Windows All Versions: Recommendation
Chances are you probably don't need to login to your administrator account, at least not on a regular basis. As I mentioned above, the most common need is to reset another account's password, or to deal with a hardware or configuration issue, both of which can be done in safe mode.
If you're facing an issue that requires being logged in as administrator "normally", consider whether you might be better served by creating a different account with administrator privileges, or in Windows Vista, if simply turning off UAC wouldn't resolve your issue.