I downloaded a DNG/CR* codec yesterday which allows you to view RAW files in Windows (but only 32 bit version). Seems to work fine. I wanted one to view PSD file, but there no longer seems to be one on Adobe. There are several mentions on Google which seem to indicate that it caused problems in Windows. Although, you can of course use Photoshop Bridge as a general viewer, and load Excel/Word files etc from there.

DNG Codec - Adobe Labs