Advanced SystemCare software?

I saw Advanced SystemCare from the most popular download at CNET. Can I use it or is it too risky?

Registry cleaners/optimizers are not recommended for several reasons:

• Registry cleaners are extremely powerful applications that can damage the registry by using aggressive cleaning routines and cause your computer to become unbootable.
  
  The Windows registry is a central repository (database) for storing configuration data, user settings and machine-dependent settings, and options for the operating system. It contains information and settings for all hardware, software, users, and preferences. Whenever a user makes changes to settings, file associations, system policies, or installed software, the changes are reflected and stored in this repository. The registry is a crucial component because it is where Windows "remembers" all this information, how it works together, how Windows boots the system and what files it uses when it does. The registry is also a vulnerable subsystem, in that relatively small changes done incorrectly can render the system inoperable. For a more detailed explanation, read Understanding The Registry.
  
• Not all registry cleaners are created equal. There are a number of them available but they do not all work entirely the same way. Each vendor uses different criteria as to what constitutes a "bad entry". One cleaner may find entries on your system that will not cause problems when removed, another may not find the same entries, and still another may want to remove entries required for a program to work.
  
• Not all registry cleaners create a backup of the registry before making changes. If the changes prevent the system from booting up, then there is no backup available to restore it in order to regain functionality. A backup of the registry is essential BEFORE making any changes to the registry.
  
• Improperly removing registry entries can hamper malware disinfection and make the removal process more difficult if your computer becomes infected. For example, removing malware related registry entries before the infection is properly identified can contribute to system instability and even make the malware undetectable to removal tools.
  
• The usefulness of cleaning the registry is highly overrated and can be dangerous. In most cases, using a cleaner to remove obsolete, invalid, and erroneous entries does not affect system performance but it can result in "unpredictable results".

Unless you have a particular problem that requires a registry edit to correct it, I would suggest you leave the registry alone. Using registry cleaning tools unnecessarily or incorrectly could lead to disastrous effects on your operating system such as preventing it from ever starting again. For routine use, the benefits to your computer are negligible while the potential risks are great.

• Ed Bott's Webog: Why I don't use registry cleaners
• Do I need a Registry Cleaner?

thanks a lot

And that includes CCleaner.

I thought ccleaner is ok?

It's fine as long as you don't touch registry part.

Broni's post pretty much covers it. But I still wanted to throw my 10 cents worth in...

I once bought into the marketing trap that a regularly cleaned registry made for a happy computer (and a happy user!) It took a slightly messed up computer for me to realize that the registry cleaner marketers were wrong. My computer still worked but had "issues" from the moment I "cleaned" the registry.

In my opinion...

Don't fall for the anecdotal stories about how "I've used XYZ registry cleaner for years and never had an issue. And my computer has never ran faster/better". All they have been is lucky. Their computer is not objectively faster, it just seems subjectively like it is. Want a clean, fast computer? Do a re-install of Windows without any frivolous software.

At one time, even Microsoft made a registry cleaner (the final release was Jan 2002.) So a cleaner must be ok right? Wrong! They pulled their cleaner 11 years ago and made it clear registry cleaners are NOT necessary.

If you must do registry cleaning, do it manually. Of course, that requires that you be EXTREMELY cautious (which is really how registry editing should be approached.) One of the better tools for manual registry editing (because of it's search capabilities) is Nirsoft's RegScanner. Just keep in mind it is like a sharp knife. In the wrong hands, it's very dangerous!

every week I ran the registry to clean. Should I stop use it?

Yes. The main point is that cleaning registry doesn't bring any gains but it can easily mess things up.
No reason whatsoever to use any.

Han has very nice points there.