Every time I turn off my computer, I receive a pop-up message saying "XPCom: Event Receiver". I thought it was another kind of virus so I made some research to confirm what is it and why am I receiving it. I found this article below which is very informative and helpful. It has guidelines on how to resolve the error and to prevent it from re-appearing. The good this is - it's not a virus!!!
There have been isolated reports of people getting an error message when they try to shut down Windows or when they are browsing the web with Mozilla Firefox. The error has to do with the XPCom: Event Receiver. The problem seemed to be connected to old versions of Firefox and some wonky anti-virus software. However, since the release of Firefox 2, the problem has started to reappear.
MozillaZine has a forum thread that is covering this problem. Check there first to see if a fix has been found. At the time of this writing, it has not.
Many users that have reported this problems are still running Windows 98. Since Windows 98 is no longer supported by Microsoft, it is highly advisable to upgrade your PC to Windows 2000 or Windows XP.
Otherwise, the following techniques seem to have worked for some:
1) If you upgraded from a previous version of Firefox, uninstal the program and reinstall.
2) If you continue to get the error, try disabling all of your Firefox extensions.
3) Make sure that you don't have competing anti-virus and anti-spyware programs running. One anti-virus program and one anti-spyware program will suffice in most cases. You should never run more than 1 anti-virus program at the same time. Running more than 2 anti-spyware programs at the same time could also cause problems.
4) Check your firewall settings. If you are running a 3rd-party firewall, make sure that the Windows firewall has been disabled.
5) Update all of your security programs (anti-virus, anti-spyware, firewall) to their latest versions.
Source: Help2go.com
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