Firefox hangs after about an hour of use, regardless of actual use volume, sites visited, etc. 1. Other browsers will function. 2. It will clear if I shut down Firefox and End Process at Task Manager (win7 still) 3. Clearing it will not resolve long term, as about an hour later, it will hang again. 4. Sample sites, Facebook, a few game sites, ESPN, Yahoo(mail), Have run virus and malwares - with no atypical results. Have cleared cookies, and attempted most Firefox trouble shooting methods in the knowledgebase. Have a few plug-ins (no-script, theme font and size changer) in use. But, the sites are the normal ones visited, prior to this trouble, as well as after, with no changes to either plug-in.