Re: how to uninstall inbox.com
The remaining of this toolbar lies on Control Panel. So the first option that you have is to check in Add/Remove programs. And then removing the add-on from Firefox. This is the most proper way of deleting the files installed with this toolbar. The most you can do is re-install Firefox to get rid of this completely. You must avoid such stuff as they contain malware infection. It is recommended to use a good internet security tool which can control this apps.
Re: how to uninstall inbox.com
There is a software called as Crawler Toolbar Uninstaller. This can be used to remove inbox.com toolbar from your system. It is very easy to use and wipes out the toolbar files. You can also use CCleaner for that purpose. Once you done with the uninstallation stuff do not forget to wipe out Windows temp folder also. If still you feel that this toolbar is active in your system, download and install Hijackthis. This tool can generate a detail log report of each and every application running in Windows and you can manually delete that from the mentioned location.