Firefox crashes when i go to yahoo mail and youtube

Question

== Issue
==
Firefox is having problems with certain web sites
== Description
==
When I first downloaded and installed Firefox, all the sites were working just fine. I went around YouTube watching videos, went to my Yahoo! mail, etc. But, later on, when I tried to visit YouTube again, Firefox kept crashing. I thought if I just shut down my laptop and waited until the next day, it would be fine. But, I visited Yahoo! mail first, and everything was fine for about 5 minutes, but then Firefox suddenly crashed. I opened up Firefox again, visited Yahoo! mail again, and Firefox crashed once more. I went around Mozilla for help, and I noticed that other people have had this problem too. I tried to fix it by going into 'My Computer' and deleting that plugin stated in the help page, but I can't seem to find anything in my computer. So help please on how I can fix this? Thanks in advance!
Also, I had restored my laptop to its factory settings right before installing Firefox (because my laptop had problems), so would this affect it in any way? Before I restored to factory settings, my laptop never had these problems with Firefox.
== URL of affected sites
==
http://mail.yahoo.com/ , http://www.youtube.com
== Troubleshooting information
==
Application Basics
Name Firefox
Version 3.6.6
Profile Directory
Open Containing Folder
Installed Plugins
about:plugins
Build Configuration
about:buildconfig
Extensions
Name
Version
Enabled
ID
AVG Safe Search 9.0.0.825 true {3f963a5b-e555-4543-90e2-c3908898db71}
AVG Security Toolbar 4.504.019.002 false avg@igeared
Modified Preferences
Name
Value
browser.places.smartBookmarksVersion 2
browser.startup.homepage_override.mstone rv:1.9.2.6
extensions.lastAppVersion 3.6.6
network.cookie.prefsMigrated true
places.last_vacuum 1279156016
privacy.sanitize.migrateFx3Prefs true
== Firefox version
==
3.6.6
== Operating system
==
Windows XP
== User Agent
==
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.6) Gecko/20100625 Firefox/3.6.6
== Plugins installed
==
*-Default Plug-in
*The QuickTime Plugin allows you to view a wide variety of multimedia content in Web pages. For more information, visit the QuickTime Web site.
*Shockwave Flash 10.1 r53
*iTunes Detector Plug-in
*DRM Netscape Network Object
*Npdsplay dll
*DRM Store Netscape Plugin

Answer 1

Hello Teresa.
Unfortunately, the computer doesn't work with waiting for issues to fix themselves, by themselves. Unless this is an error with the sites themselves (unlikely), it's possible that you are having a problem with some Firefox add-on that is hindering your Firefox's normal behavior. Have you tried disabling all add-ons (just to check), to see if Firefox goes back to normal?
Whenever you have a problem with Firefox, whatever it is, you should make sure it's not caused by one (or more than one) of your installed add-ons, be it an extension, a theme or a plugin. To do that easily and cleanly, run Firefox in [http://support.mozilla.com/en-US/kb/Safe+Mode safe mode] (don't forget to select ''Disable all add-ons'' when you start safe mode). If the problem disappears, you know it's from an add-on. Disable them all in normal mode, and enable them one at a time until you find the source of the problem. See [http://support.mozilla.com/en-US/kb/Troubleshooting+extensions+and+themes this article] for information about troubleshooting extensions and themes and [https://support.mozilla.com/en-US/kb/Troubleshooting+plugins this one] for plugins.
If you need support for one of your add-ons, you'll have to contact its author.
If the problem is not disappears when all add-ons are disabled, please tell me, so we can work from there.