What about Guest Accounts in Windows Vista?

Users with a Guest Account can use PC
 
Guest accounts are the accounts prepared for users who don’t have a permanent account on the computer.
Using the guest account with no password, anyone can quickly log on, receive and send mails, or browse the Internet.
Guest account users cannot open the encrypted files and folders, or change settings.
■When logging on with a guest account, we can perform the following operations
•We cannot install new software or hardware, but can operate software already installed on the computer.
•We can change the picture for the guest accounts.

Turn on or turn off a guest account, please refer to the following information.
How to turn on or turn off a guest account in Windows Vista.

Guest account has several special functions related to the security and network sharing, so please do not set them as disable.
After setting guest account as disable, software based on enable guest account may not work normally.

After closing guest account, the guest account will not be displayed on the login screen, but it will not turned into disable status.