The Administrator account exists in Windows 7, (as well as it exists in Vista), but it is disabled for security reasons. It may be enabled on a few ways, but we found that the way described below is the fastest way:
1. Click on Start button
2. Type “cmd” at “Search programs and files” field
3. Right click on “Command Prompt” and select “Run As Administrator“.
4. At command prompt type the following command: “net user administrator /active:yes”
The Administrator account is enabled.
If you want to disable it again, type the following command:
“net user administrator /active:no”