Is there any reliable software that will actually clean up your PC?

Do off-the-shelf software products which claim to "Clean Your PC" work?

• It's these incessant commercials I always see on my TV. "Install our product, and we will make your PC up to 100% faster!" Then they usually go through a few customer use cases (typically involving elderly folk) about how they installed it and found they could read e-mails much quicker and that their startup time was cut in half, their programs loaded quicker, and many more wonderful and seemingly desirable things. Being a software engineer I am skeptical of these commercials and these products. I understand there can be registry errors (one of the things they say they can fix) and that there could be other programs unnecessarily running on startup which could slow boot time, and a severely fragmented disk which could slow seeking and loading files, but really? Do these products do anything useful, other than make their developers rich? And furthermore, if they claim to fix registry errors, how do they know what was supposed to be in the registry in the first place on third party software, as far as I know there is no central "this is what a registry should look like" database? I guess I'm just skeptical about software which claims to be the end-all of software issues. But please, you thoughts? Question: Do these products provide measurable speed increases or decrease the frequency of crashes/freezes on one's system as a result of using them? Here are some specific examples: http://www.registry-cleaner.net/ CleanMyPC™ Registry Cleaner scans the Windows registry and finds incorrect or obsolete information in the registry. By fixing these obsolete information in Windows registry, your system will run faster and error free. http://www.mycleanpc.com/ Quickly clean your system and increase speed...Prevent annoying screen freezes, crashes and errors. http://www.pcdocpro.com/ Get rid of crashes, freezes, and long wait times with our 1-click software right now. http://www.cleanmypcs.com/

• Answer:

  No software application has yet been devised which can take all possible variations of system configuration into account and make appropriate decisions to optimize a randomly selected computer. That being said, there are a number of things a user can do which will (generally) improve the responsiveness of their system, the majority of which can be done without any software other than the built-in system tools (defragmenting, etc.)http://www.microsoft.com/athome/setup/optimize.aspx One "optimization" which is almost never justified, or entirely safehttp://msdn.microsoft.com/en-us/library/ms724871%28v=vs.85%29.aspx, is messing with the Windows Registry. The Windows Registry is not rigidly formattedhttp://msdn.microsoft.com/en-us/library/ms724946%28v=vs.85%29.aspx and applications may store data in it in any manner they wish (within the restrictions of the application's security context, of coursehttp://msdn.microsoft.com/en-us/library/ms724878.aspx.) This free-form construction means that it is all but impossible to definitively tell whether a key is "useless" or "useful" without being intimately familiar with the application that owns ithttp://msdn.microsoft.com/en-us/magazine/bb985037.aspx. Certainly, applications which "walk" the Registry (that is, proceed from key to subkey in a linear manner looking for a particular key) will suffer speed penalties, and those penalties will become greater in direct proportion to the number of keys the application has to look at in order to find the particular key its looking for (I have no citation for this, but to me it's common sense that looking at each key in turn is slower that just going right to the key you want.) However most applications don't do that, or at least not often, so the penalty doesn't apply to them. This fact, when taken into consideration with the fact the "pruning" the registry can have disastrous results if an error is madehttp://support.microsoft.com/kb/256986, leaves only the conclusion that whatever gains are to be had by running a registry cleaner/optimizer/defragger/etc. are outweighed by the risks. And this is not even considering that "registry cleaning" has no official definition other than what the Registry cleaner's vendor makes it. In short, registry optimizers are the modern day snake oil wonder tonic. The best advice for keeping your computer running at peak efficiency is the same advice as for everything else: take care of it. Don't install every free app you find, run a reputable and up-to-date security application, keep your software and the operating system up-to-date, periodically defrag and chkdsk your hard drives (note that SSD drives require somewhat different care and feeding than mechanical drives,) uninstall an application if you don't use it, and judiciously curtail the number of applications and services which are set to load at start.http://www.microsoft.com/athome/setup/optimize.aspx References: http://www.microsoft.com/athome/setup/optimize.aspx http://msdn.microsoft.com/en-us/library/ms724871%28v=vs.85%29.aspx http://msdn.microsoft.com/en-us/library/ms724946%28v=vs.85%29.aspx http://msdn.microsoft.com/en-us/library/ms724878.aspx http://msdn.microsoft.com/en-us/magazine/bb985037.aspx http://support.microsoft.com/kb/256986