Firefox version 3.6.12 was released this morning to fix a critical security issue in last week's version. Annoying though these frequent updates may be, you're better off with the security fixes than without. Update when prompted, or open Firefox, click Help - Check for Updates, then follow the prompts.
My favorite utility updated to version 3.00.1303 today. As always, CCleaner only updates by installing the new version. You'll need to download here, then install. Remember to download first - THEN install. Don't simply click Run during the download. If you want to know why, re-read my earlier post: http://cathycom.blogspot.com/2010/03/run-or-save.html
Another great free utility to remove spyware. Used along with Malwarebytes and Spybot, you can clean out most infections. Download here, or update your installed version.
Thunderbird is an open-source email client - a good alternative to Microsoft's Outlook Express, Windows or Live Mail. Download from and install it after download: http://www.mozillamessaging.com/en-US/thunderbird/