BleepingComputer.com: How to Disable Windows XP Professional Users

If you have a windows xp account that will be inactive for a long period of time, you can disable them instead of deleting them. To do this follow these steps:

1. Click on the Start button then click on the run option.
2. Type lusrmgr.msc into the open field and press the OK button.
3. Click on the users folder to see a list of the local users on your machine.
4. Double-click on the user that you would like to disable to bring up their properties.
5. Put a checkmark in the Account is disabled field.
6. Press the OK button.

To enable the account just remove that checkmark you placed in step 5.

Now the account is disabled and that user will not be able to log into the computer.

Please note this only works for Windows XP Professional.