This seems to be a common error some people encounter with Firefox. First, XPCOM has nothing to do with Windows XP, rather it is Cross Platform Component Object Model. It is a cross-platform component model from Mozilla (more info at Wikipedia). Not sure what causes this error other than a file or files for XPCOM in the main Firefox uninstall some how get removed or corrupted. However, the fix is fairly simple and painless: re-install Firefox. Uninstalling Firefox will NOT remove your profile folder or settings, it simply removes the Firefox browser from your computer. Once you have removed Firefox, (using another browser)…