I am adding a few comments to the wonderfull description given by binkie's 7 blog in the same category ; by no way these comments should be understood as criticizing's binkie'7 'contribution , nor are these comments supposed to be "complete " .

Binkie'7 s Contribution is a perfect roadmap , for any user of a PC running Windows (I will assume here XP or Vista , while for the latter one I have NO Knowledge . I am waiting the first wave of complaints about the "revolutionary " OS ).

OK

REGISTRY : this is the most important part of Windows as ANY user (even beginner ) SHOULD know ; in principle everything on your PC can be operated from the REGISTRY ; i just said "in principle " : REGISTRY is a very complicated part of Windows and only very talented PROFESSIONAL It's can hope to know exactly what they are doing by changing keys ;

any beginner should be frightened (it's a good desease here!!!!) by the following fact :altering a key or a data in the registry , namely EDITING the registry for altering purposes , leads to IMMEDIATE changes and no backups are taken if you do not know how to do it before altering anything ;therefore the configuration beeing altered by traficking the registry can wreck the PC and prevent it to START ; the only turnabout in that case is restoration to a previous configuration if you have restore points at your disposal and even that MAY NOT WORK AT ALL !!!!!

this beeing said , Binkie7 advices cc Cleaner to avoid unconsidered manipulations in the Registry ; two main advantages of thsi tool are: this is free software and second it takes backups of useless keys ; so in principle you are safe , using this tool ; now a piece of explanation is in order (It took me Months to understand that , so it is not unconceivable that others could encounter the same questions ) : what is exactly a registry error ??????

There are many types of such things : badly written programs write "wrong " keys , wrong information if you prefer (I am not going into details here ) ; the errors may prevent the program to work but usually they will just work including bugs which will just give you headaches ; but there are other types : the registry is a huge DATABANK for the PC , anything you perform on your PC has an inscription in the registry ; but evidently such datas are not erased automatically if useless ; therefore after a while , the registry becomes overloaded with useless datas ; this beeing the case , slowdowns are to be expected or hung apps or even worse ;

Everything which precedes  has to do with the nice operation of NERO to its full capabiliies: remember that Nero has to synchronize and work on two different levels : one is the software part and the other is the hardware part ; this makes the operation of Nero delicate to some extent ; beeing an excellent program , Nero will usually work also if the registry is full of various errors , but in case a bug occurs , diagnosticizing will be difficult (hardware failure ? software failure ? problem with your configuration ?) In every case , having a  healthy and COMPACTED registry will be an essential help for Nero to work ; now , coming back to the Tools that may perform such vital operations as cleaning and compacting , binkie7 mentions ccCleaner; I use this tool , so it cannot be my intention to say anything against this free and nice software ; however , if your configuration is complicated , if you are a power user , installing and uninstalling softwares , then CC  Cleaner might be too light ; its major drawback is the following : datas written in the registry are organized in Hives which are in a limited number ; but CCcleaner reveals only the keys which it finds obsolete or useless ; this in principle is enough for general purposes or so to speak for light cleaning ; as mentioned , CCCleaner takes backups so you may revert to the previous situation in case something goes wrong (just go into safe mode if your PC can't restart and operate the "undo " tab in CCleaner or backup (restore ) : you will be able  to do this in safe mode ;

 but if you have really wrong keys and moreover if you want to CONTROL the hives where the errors are detected , then CCCleaner will not help ; it is apparently not the place to advertise for programs which do not depend on Nero ; but allow me an exception : they are various GOOD registry cleaners ; how do they work ? As already said   , the REGISTRY is a huge databank  ; no tool will scan your registry in  every single place : this is not only absurd but would take an infinite amount of time (approximately infinite)  ; therefore ALL SUCH tools operate with algorithms and therefore TWO DIFFERENT tools may NOT AGREE on the errors found ; the best tool I found ever (not 100% , but close to perfect) is JV16 PT from Macecraft ; I would not advice to make a compromise by looking at more limited versions of JV 16 PT which limit themselves really to registry cleaning ; JV 16 PT has 16 TOOLS all linked with operating with the registry   (compacting also of course ; this does not need explanation: the smaller the registry , the  better your PC will run ) and this  program is really exceptional : have a look to it ; it's not freeware but close of freeware: the license is lifelong   , cheap  and valid for all coming versions ! It scans ultimately fast , repertoriates the errors by seriousness and of course allows you to scan each hive separately ; this is of extreme usefulness and brings you to  the very top of safety ;  of course you may take backups , even of individual suspect KEYS. This program allows you so many various tasks , including UNINSTALLING programs the right way , that I cannot miss advocating it .

Why insisting on uninstalling ?

the reason is that when you uninstall ta given program using eg ADD / REMOVE in configuration panel of Windows , it happens more   than once that the uninstaller lets behind some keys  belonging to the UNINSTALLED program ; why is that ? Too many reasons ; the most probable is that editors want their programs to be INSTALLED , not UNINSTALLED , therefore they do not care too much on Uninstalling . therefore the leftovers (wrong keys) fill up your Registry and this may leadto conflicts between  apps or worse . JV16PT REALLY CLEANS THE REGISTRY ; it may not work well in RARE CASES ..... Including NERO .!!!!!

This will be my next subject .    

My apologies for my bad english but my native language is French .