Getting administrator privileges
Sometimes you are instructed "log on as administrator", or "make sure you have administrator rights", or "you must have administrative privileges" before doing something. Those all mean the same thing: you must be an administrator in order to proceed. An administrator has the right to modify anything on a computer. Non-administrators have restricted rights and so are not allowed to do certain things. If you are told to get administrator rights, it's because what you're about to do cannot be done (or would be done improperly) if done by a non-administrator. Installing or uninstalling drivers should be done only by administrators. Sometimes, non-administrators can do things which can supposedly only be done by administrators but it's not a good idea to try. Some things which require administrator rights do not always fail gracefully if done by non-administrators.
The previous two error messages are examples of what you'll see if you try to install display drivers when you do not have administrator rights.
Unfortunately, you can also get cryptic error messages like the one above. Most of the time the error messages mention "administrator" but that's not always the case. So when you're installing or uninstalling drivers (or just about anything else), you should always make sure you have administrator rights because if you don't, you may not be able to figure out what's going wrong.
In Windows 95, Windows 98, and Windows ME, all users are allowed to modify eveything so you don't have to worry about administrator rights. Windows 2000 and Windows XP make a distinction between administrators and other users. If you've barely heard of "administrator rights" then you probably already have them. Any user accounts which you create while installing Windows are given administrator rights by default. So if you did a standard Windows installation and nothing else, then you already have administrator rights. Most pre-built computers also are rigged so that you end up with administrator rights if you just boot Windows normally and do the default logon.
The easiest way to tell if you have administrator rights under Windows 2000 and Windows XP is to right-click the "Start" button. If the menu which pops up includes the "Open All Users" and "Explore All Users" entries, then you have administrator rights.
If you don't already have administrator rights, then you have to log off of the current account and log onto an administrator account to get them. To do that in Windows 2000, click "Start", "Shut Down", select "Log Off", and then log back on using an administrator account. You will probably have to know a password to log back on. In Windows XP, click "Start", "Log Off", log that user off, and then log back on using an administrator account. You may also have the "Switch User" option. That switches to another user without shutting down any programs which are currently running. It's best not to use switch user when installing or uninstalling because you will often have to reboot to complete the operation. If you're running Windows XP and you can't find an administrator account, then boot in safe mode (instructions here). An administrator account may then show up in the safe mode login screen.