To enable the account, you have to log into the system with administrator rights. However, it is possible that disabled and uchetku administrator. In this case you need to boot in safe mode. After turning on the computer, wait for single beep, POST, and press F8. In the boot menu choose "Safe mode". On request the system to continue work in this mode, answer Yes.
If your computer has Windows XP, to display the context menu, right-click on the icon "My computer" and select "Manage". Activate the item "utilities", open the snap-in "Local users and groups" folder and then "Users".
How to enable an account if they are all disabled
Right button click on the administrator account and select the "Properties" command. Remove the flag next to "Disable". In the same way turn on the account you want. Restart the computer in normal mode.
In the 7th version of Windows, administrator account is disabled by default because of security reasons. To enable this, from the start menu start search bar and type in the command cmd.
In the console window type:

net user Administrator /active:yes.

After the system answers, enter the administrator password:

net user Administrator *password*.

This method is also suitable for versions of XP and Vista.
Is there another way to enable the administrator account. In the search bar, type secpol.msc. In the left part of the window "security Settings" snap-in, expand the "Local policies" and select "security Settings". The right side locate the "account Status Administrator". Click it to open the context menu with the right mouse button and choose "Properties". Put the switch in position Enable. In the same way you can also include other account.
Method using local policies also suitable for switching user accounts in Windows Vista. To cause the snap-in "Local policies" in this version, in the search line, enter mmc. If prompted to authenticate, type your Admin password.