Note: by default user added will belong to Users group (ASPNET user too, thats the only requirement)
To create ASPNET user, follow these steps:
1. Open Computer Management. To open Computer Management, click Start, point to Settings, and then click Control Panel. Double-click Administrative Tools, and then double-click Computer Management.
2. In the console tree, in Local Users and Groups, click Users.
3. Click Action, and then click New User.
4. Type ASPNET in User name box and check Password never expires check boxes.
5. Click Create, and then click Close.