Firefox's built-in proxy settings are in a little bit of an obscure location: orange Firefox button (or Tools menu) > Options > Advanced > Network mini-tab > "Settings" button If you had a quick, convenient way to access proxy settings, perhaps you were using an Add-on for that? Most likely, it would have been an extension. To see whether the extension has become disabled, you can check on the Add-ons page and try to update and/or reenable it. Either: * Ctrl+Shift+a * orange Firefox button (or Tools menu) > Add-ons In the left column, click Extensions. Disabled extensions cluster toward the bottom on a gray background. If it can't be re-enabled, try using the "gear" button above the list to "Check for Updates". Any luck?