Personally, I wouldn't touch it. There are few programs I would trust to make widespread registry changes, they are also quite vague on what it actually does and how it works.
If I'm being told my PC has system instability, I would like to know specifically what's wrong, rather than the vague description "Windows needs repairing".
Virus Total Scan
WOT Forum Discussion.
Whether it's legit or malicious or not seems to be debatable. The scanner itself doesn't seem to come with any malware, although there are a few things in the license agreement that I dislike:
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Upon running a scan, the program did provide me with accurate and useful information about my system. It also compared my system specs with average specs (which it claims were worldwide averages).
The problem comes when it reaches the PC Stability stage. I was told upon running the scan, that virtually all of my programs have crashed at some point, and that this is "repairable in most cases".
The only problem here, was several of the programs listed are not actually installed on my computer. A couple were programs previously installed, and at least one program on the list has never been installed at all.
Apparently my PC has 74% Stability. - I keep my computer in good shape, and regularly maintain this.
In my opinion, this program is not necessary, and will exaggerate your computer problems in order for you to buy the product. It doesn't appear to distribute any malware, but I would consider it a questionable product.
If you are experiencing problems, there are much better ways of dealing with them.