Registry Prot

Registry Prot is a fine stand-alone, compact, low-level real-time registry monitor and protector.

http://www.diamondcs.com.au/freeutilities/regprot.php

Context Explorer

Context Explorer is a Firefox plug-in that uses an open-source desktop indexer to automatically associate your local resources to the pages you’re browsing. Reduce the distance between the Internet and your desktop in a way that is effortless and self-adaptive. You shouldn’t be faced with your entire system all the time. You should just see what you want, when you want it.

http://organicdesktop.com/