If you’ve ever entered a password in your Web browser or e-mail client, or provided a password for an encrypted disk image, your Mac has probably asked whether you’d like to save that password to your Keychain. In addition to accessing your keychain through these dialog boxes, you can work directly with your Key-chain via Keychain Access (Applications: Utilities). When you launch Keychain Access, you see a list of all the items in your Keychain, including information about each item’s name, kind, creation date, and modification date.
As for the scanner have you tried to quit the application or uninstall it completely and reinstall it?
To check how much free space is available on your startup disk:
In Finder, select your startup disk's icon. For most users, this is Macintosh HD.
Press the Command-I keyboard combination or right click and get info.
The Get Info window for your startup disk will open. In the General pane, the Capacity, Available (free space), and space Used on your startup disk will be displayed
You can employ any of the following tips to increase the free space available on your Mac OS X startup disk without altering your hardware.
1. Empty the Trash
2. Archive old files
3. Clean up system logs and temporary files
4. Remove unused localization files
5. Delete the Previous Systems folder from a prior Archive and Install
6. Uninstall unused applications
7. Delete old iTunes Library file backups
If you find your Mac OS X startup disk has become full unexpectedly:
Check Console for clues. In particular, examine the various Console logs for large blocks of identical, repeating messages. Such blocks of repeating messages often indicate a runway process is logging excessively due to either a flaw in the process itself, its logging parameters, or a problem with your Mac. Excessive logging can result in log files growing without bounds.
The freeware utilities OmniDiskSweeper and WhatSize are great for finding large, invisible files. Take care to be sure you understand the purpose of a large file before you delete it. In particular, Virtual Memory (VM) Swap files, located in the /private/var/vm directory, should not be deleted while your Mac is running. VM Swap files are created and released dynamically by Mac OS X.
Also if you delete apps use app delete rather than just dragging items to the trash which still leaves folders in the system taking up space. With app delete you get everything and hopefully this will fix your issues with your ibook, best of luck.