Crashing Problem with Firefox Web-Browser

hi there.........

I have FireFox 3.0.5 and every time before closing it closes down, without any kind of errors occurring, I get a window message pop up apologizing for the fact that FireFox has been crashed for some and asking to send a error report.

Why do I keep getting this error message when there has been no error?

Is this due to some virus or is it just my system?

Please provide some suggestion regarding this problem...............

According to me,

Use the latest version of Firefox:

Firefox updates are regularly released and a number of the fixes are crash related. One of the first, and easiest, things to check is to make sure you're using the latest release. See Updating Firefox for details.
Problematic or out of date extensions or themes

Extensions and themes can often cause crashes and other errors. This is especially true if you recently installed or updated an extension. Follow the steps in the Troubleshooting extensions and themes article to determine whether an extension or theme is causing your problem. The support articles for various specific symptoms of Firefox crashes include lists of extensions that may cause certain crashes.

Problematic or out of date plugins

Plugins are programs that let Firefox display video and sound and do other things. If you find that certain, specific pages cause Firefox to crash every time you visit them, they may need a common plugin. Follow the steps at the Troubleshooting plugins article to determine whether a plugin is causing your problem.

Malware: viruses or spyware

A number of different viruses and spyware are known to crash Firefox. Ensure that your system is kept clean of spyware and viruses. For more information, see Is my Firefox problem a result of malware.

Close down Firefox completely: At the top of the Firefox window, click the File menu, and select the Exit menu item.
In Windows, click Start, open the All Programs list, and navigate to the Mozilla Firefox folder. In the Mozilla Firefox folder, select Mozilla Firefox (Safe Mode).
Firefox should start up with a Firefox Safe Mode dialog.

1. Click on the Start button and select Search to open the Search Results window.
   
2. On the left side of the Search Results window, click on the All files and folders link.
   
3. Click to expand the More advanced options list.
   
4. Put a check mark next to Search system folders, Search hidden files and folders, and Search subfolders.
   
5. In the All or part of the file name field, type xpicleanup.dat.
   
6. Click Search to begin the search.
   
7. If any results are returned, delete them.
   
8. Restart Firefox.

1. Close down Firefox completely: At the top of the Firefox window, click the File menu, and select the Exit menu item.
   
2. In Windows, click Start, open the All Programs list, and navigate to the Mozilla Firefox folder. In the Mozilla Firefox folder, select Mozilla Firefox
3. Firefox should start up with a Firefox Safe Mode dialog.
   
4. When the Firefox Safe Mode window appears, press the button Continue in Safe Mode.
   
5. If the problem persists in Safe Mode, your problem is not being caused by an extension or theme. It could be caused by a plugin - plugins are not disabled in Safe Mode. See Troubleshooting plugins.
   
6. If the problem is not present in Safe Mode:
   
7. One of your Firefox configuration files may be corrupt. Reset your toolbars and controls to see if that solves your problem.
   
8. The theme you're using or one of your extensions could be the causing the problem.