I had the same problem (printer worked, but scanner and card readers did not) with my Lexmark X5470 after updating to Snow Leopard. Lexmark CS (or lack thereof) was of no help. For months, I haven't needed the scanner until today, so I dug around Lexmark's website. I found that on 11/19/2009 Lexmark released a driver file called "Lexmark 5400 Web Installer 10.6.dmg". With my hopes up, I downloaded and installed the driver. First, the bad news: it installed a "new" 5400 Series printer (in the Print & Fax Preference tab under System Preferences) but with very few options, and the tab for Scan was gone. My "original" Lexmark 5400 Series printer was listed still, but the Scan tab went to a screen that continued to say Scanner not Connected. Now, the good news: I realized after installing the driver that I hadn't restarted. So, restart I did, and, what do you know? I went back to the Print & Fax Preference tab, and I saw that the printer listings (both my original one and the new one it created) had functioning Scan tabs. In addition, the Image Capture application works once again with the X5470. Thus, I am now back in business with full functionality with the printer, scanner, and card readers.