What is ccleaner? Its a free program that is suppost to clean your harddrive of unused and unwanted files. Pro's: It's free. Cons: It fiddles with your registry (like gary glitter in a school yard) and does some dodgy stuff like completely removing the registry!!! And removing wanted files Here are some proper reviews: I have been using Ccleaner for around a year and have had great results with no problems whats so ever. My PC has been running sluggish and freezing up in EI7 online but McCafee is up to date and can find no malware, no spyware is coming up either. I have spend two months working on medical research for my disability appeal and had a couple hundred articles many of which had to be accessed from a hospital or university network PC for institurional access. My daughter turned the PC on to go to Webkinz and some hostsvc.exe error was on the desk top start up screen. I decided to run Ccleaner (Windows, Applications and Registry) and I noticed an abnormally high number of Word documents on the list classified as "Temp" files so I cleaned as usual. I had opened up fifty or so documents last up time searching for a document I had saved but could not find so I thought that explained it. Next thing I know ALL my documents are gone and there's nothing in the recycle bin. I tried a system restore to before my documents disappeared but no luck. There are some how some previous versions of the My Documents and sub file headings showing up but only 10-20 files and lke seven folders. My hard drive has plenty of space and the HD monitor indicates no errors. What the heck happened and is there any hope for recovering my files? No sir you're medical research is in burning in ccleaner hell now! (not actually caused by ccleaner) EDIT: Discussion on this review HERE (click here)