SYMPTOMS
When a person checks the User accounts he/she finds a strange account,called-"ASP.net" account.

CAUSE
ASP.NET Machine Account is created when the Microsoft .Net Framework 1.1 is installed onto a Windows XP machine.

RESOLUTION
In September 2004 Microsoft released Service Pack 1 for version 1.1 of the .Net Framework, the automatic logon issue was corrected along with further security enhancements, and full support for Windows XP Service Pack 2. To download Service Pack 1 for the framework click here (10.2Mb Download).

Alternatively:-Start > Run and type in "control userpasswords2" >Ok.
Uncheck "Users must enter a user name and password to use this computer" option, and click Ok.

MORE INFORMATION
If one works with asp.net development work then he/she must keep that account,otherwise ASP.net projects will no longer function correctly.