hello, could you go to the firefox menu ≡ > help ? > troubleshooting information, copy the contents of that page and paste them here into a reply on the forum? this might give us a clue what is going on...

Info requested is below. I removed all lines regarding printer as the reply was too large for your form.

Application Basics Name Firefox Version 33.1.1 Update History User Agent Mozilla/5.0 (Windows NT 6.1; WOW64; rv:33.0) Gecko/20100101 Firefox/33.0 Profile Folder Enabled Plugins about:plugins Build Configuration about:buildconfig Memory Use about:memory Multiprocess Windows 0/1 Crash Reports for the Last 3 Days Report ID Submitted

All Crash Reports (including 1 pending crash in the given time range) Extensions Name Version Enabled ID Norton Toolbar 2014.7.9.8 true {2D3F3651-74B9-4795-BDEC-6DA2F431CB62} Graphics Adapter Description NVIDIA GeForce GTX 650 Ti Adapter Drivers nvd3dumx,nvwgf2umx,nvwgf2umx nvd3dum,nvwgf2um,nvwgf2um Adapter RAM 1024 Device ID 0x11c6 Direct2D Enabled true DirectWrite Enabled true (6.2.9200.16492) Driver Date 11-11-2013 Driver Version 9.18.13.3182 GPU #2 Active false GPU Accelerated Windows 1/1 Direct3D 11 (OMTC) Vendor ID 0x10de WebGL Renderer Google Inc. -- ANGLE (NVIDIA GeForce GTX 650 Ti Direct3D9Ex vs_3_0 ps_3_0) windowLayerManagerRemote true AzureCanvasBackend direct2d AzureContentBackend direct2d AzureFallbackCanvasBackend cairo AzureSkiaAccelerated 0 Important Modified Preferences Name Value browser.cache.disk.capacity 358400 browser.cache.disk.smart_size_cached_value 358400 browser.cache.disk.smart_size.first_run false browser.cache.disk.smart_size.use_old_max false browser.cache.frecency_experiment 2 browser.places.smartBookmarksVersion 7 browser.search.suggest.enabled false browser.search.useDBForOrder true browser.sessionstore.upgradeBackup.latestBuildID 20141113143407 browser.startup.homepage https://login.comcast.net/login?s=portal&ts=4574904e&continue=http%3a%2f%2fxfinity.comcast.net%2f browser.startup.homepage_override.buildID 20141113143407 browser.startup.homepage_override.mstone 33.1.1 browser.tabs.loadInBackground false browser.urlbar.default.behavior 2 dom.mozApps.used true extensions.lastAppVersion 33.1.1 font.internaluseonly.changed true font.name.serif.x-western Arial gfx.direct3d.last_used_feature_level_idx 0 media.gmp-gmpopenh264.lastUpdate 1415390775 media.gmp-gmpopenh264.version 1.1 media.gmp-manager.lastCheck 1416663198 network.cookie.prefsMigrated true places.database.lastMaintenance 1416666985 places.history.expiration.transient_current_max_pages 104858 plugin.disable_full_page_plugin_for_types application/pdf plugin.importedState true privacy.clearOnShutdown.cookies false privacy.clearOnShutdown.downloads false privacy.clearOnShutdown.formdata false privacy.clearOnShutdown.history false privacy.donottrackheader.enabled true privacy.sanitize.migrateFx3Prefs true privacy.sanitize.promptOnSanitize false privacy.sanitize.sanitizeOnShutdown true storage.vacuum.last.index 1 storage.vacuum.last.places.sqlite 1414412270 user.js Preferences

Your profile folder contains a user.js file, which includes preferences that were not created by Firefox. Important Locked Preferences Name Value JavaScript Incremental GC true Accessibility Activated false Prevent Accessibility 0 Library Versions Expected minimum version Version in use NSPR 4.10.7 4.10.7 NSS 3.17.2 Basic ECC 3.17.2 Basic ECC NSSSMIME 3.17.2 Basic ECC 3.17.2 Basic ECC NSSSSL 3.17.2 Basic ECC 3.17.2 Basic ECC NSSUTIL 3.17.2 3.17.2 Experimental Features

thanks, this might happen when firefox is not able to properly save preferences in its profile folder. please try this: Click the menu button ≡ and then click help ? > troubleshooting information > profile folder - "show folder". then a new window will open up. in this window look out for a file named user.js (it might be used to overwrite your custom settings). in case it is present , delete or rename this file and restart firefox afterwards.