Having used a few registry tools and optimisers I was interested in Sept 2006 PC Authority test of Windows Registry tools and said that even though PC tools Registry Mechanic was good AMUST was in a different league. I did a lot of web research and found many Windows MPV's reckon it's the 'ducks gut's'. As I use CCleaner, Advanced System Optimizer, and MyregistryCleaner 2.1 on a daily basis I didn't expect much. Downloaded full version for 30-day eval and went into Advanced mode. Run scan and oh my G0d 510 problems, howcan this be? Fix and registry compaction and ran it again a day later with another 43 errors. After reg defrag and compaction with O&O Defrag Pro v8 in between it now scans clean. Pc boots clean and quick and everything is better. If you use Windows this and CCleaner are invaluable, definitely try them. One more registry compaction and disk defrag to go and I reckon it's as tuned as it could be.