If you select the option to "Remember me on this computer," the Orkut sign-in page will remember your username and password for up to two weeks, unless you sign out of your Google Account. Select this option if you're the only person using the computer. You should never select it if you're using a publicly accessible computer, or if you're sharing the computer with others, to prevent your Orkut profile (and other Google products) from being open to anyone who uses the same computer after you.
Prevent the web browser from remembering your sign-in information
If your information is being saved on a computer and you don't want it to be, first, check if the option "Remember me on this computer" is enabled. In this case, delete your browser's cache and cookies to disable the feature. Additionally, each time you sign in to Orkut, make sure the "remember me" checkbox isn't selected.
If the "remember me" option isn't enabled, double-check if the "form autofill" (or "AutoComplete") feature is enabled in your browser's settings. For specific information on how to disable this feature, see your browser's help center. Google Chrome users can learn more about autofill here.