From MozillaZine Knowledge Base

I'm not sure where to add this, but we might want to add information about the npystate.dll which causes yahoo mail to crash. More info here: http://community.bluesecurity.com/webx?14@234.F933a8Jqi9n.0@.3c4e1f12/0 --Lethargy

I have added the information about the yahoo plugin, but it probably needs to be cleaned up a little. I also think we may want to start a section about Yahoo crashes, seeing as how there are a few open bugs on the problem in addition to the npystate.dll crash, plus it seems to be frequently reported in the forums. --Lethargy

Yahoo Messenger Firefox Plugin Issue

The above link is broken, but the following from Yahoo Answers worked for me:
Open C:\Program Files\Yahoo!\shared folder, then rename the file "npYState.dll" to "XnpYState.dll". This will disable the plugin.
--jdmarch

Windows Firewall

If you are using Windows XP SP2, a known Windows fault may cause Firefox and other web browsers to crash after a few minutes if you have disabled the built-in Windows Firewall. Microsoft has a support page detailing this problem, <snip>

I believe the Windows firewall does not cause a crash per se. That section probably does not belong here -- but where? --AnotherGuest.

I don't believe that section belongs here, either, since the "Computer browser service" that may be stopped when disabling Windows Firewall isn't about a Firefox crash or about any web browser, but is about browsing a computer network. Ref: Description of the Microsoft Computer Browser Service The primary function of the browser service is to provide a list of computers sharing resources in a client's domain along with a list of other domain and workgroup names across the wide-area network (WAN). I removed the section. I don't think it belings anywhere on the KB, really, since it is a Windows XP networking issue, not a web browser issue at all. Alice Wyman 23:37, 18 July 2006 (UTC)