Hi,
As other Bros suggesting Ccleaner..i think it only cleans registries but not optimize them.. as u asking for optimization also..there is one application that can do optimization also..its tool ..
Registry Cleaner + Registry Optimizer..they can clean and optimize registries as they are the best optimizers..!!
it has also some useful tool
Disk Optimizer
Disk Tool
System Cleaner
System protection its for scannig Viruses and Spyware.
Glary Utilities. It's a wonderful tool for all type of pc maintainance... just like TuneUp, but it's free.. And it is both a registry cleaner and optimizer... Many other functions too.