Firefox 6 & 7 may have more than one problem causing freezes/hangs, &/or sites being slow or not completing loading. See for instance * [/questions/763205?page=3#answer-260533] It may be worthwhile considering adjusting the preference that allows multiple connections from 256 to something like 50 * https://support.mozilla.com/en-US/kb/Firefox%20never%20finishes%20loading%20certain%20websites#w_lower-the-max-number-of-http-connections ----- Some comcast supplied software was implicated in some firerox crashes recently, but you do not appear to have that problem.