In Windows 95, Profiles are turned on or off through the Passwords applet of the Control Panel. In Windows 98, they're handled through the Users applet of the Control Panel. Profiles make use of usernames and passwords. The form asks you to type your username and password. If you type a username and password that Windows does not recognize, it asks if you want to create a new logon identity.
Profiles work very well and have only a few drawbacks.
Let's get the drawbacks out of the way first. First, a PC that uses Profiles won't boot itself up. It stops after a reboot and waits for someone to type a name and password. If you used a computer as a network server, to give just one example, Your network would never come back up. Second, a PC that uses Profiles needs extra drive space.