dom.ipc.plugins.enabled false
dom.ipc.plugins.enabled.npctrl.dll false
dom.ipc.plugins.enabled.npqtplugin.dll false
dom.ipc.plugins.enabled.npswf32.dll false
dom.ipc.plugins.enabled.nptest.dll false

I see from your list of plugins that you have the "Adobe PDF Plug-In For Firefox and Netscape "9.5.1" in Windows XP. Could you post a link to a PDF file that won't open in Firefox? Here is a sample PDF file ... does it open? *http://www.adobe.com/support/products/enterprise/knowledgecenter/media/c4611_sample_explain.pdf If the above file doesn't open either, maybe something here will help: *[[Use the Adobe Reader plugin to view or download PDF files]] *[[View PDF files in Firefox without downloading them]] I also see that you have disabled the Out-of-Process Plugins (OOPP) crash protection feature in Firefox, since your modified preferences show: dom.ipc.plugins.enabled false dom.ipc.plugins.enabled.npctrl.dll false dom.ipc.plugins.enabled.npqtplugin.dll false dom.ipc.plugins.enabled.npswf32.dll false dom.ipc.plugins.enabled.nptest.dll false I would suggest resetting all of those preferences to re-enable OOPP if you are having plugin problems. Ref: * http://kb.mozillazine.org/Resetting_preferences#Resetting_preferences_in_about:config * http://kb.mozillazine.org/Plugin-container_and_out-of-process_plugins

You have a lot of extensions installed.<br /> Did you check for any problems caused by them? Start Firefox in <u>[[Safe Mode|Safe Mode]]</u> to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance/Themes). *Don't make any changes on the Safe mode start window. *https://support.mozilla.org/kb/Safe+Mode *https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes