It's good to clean temp folders, browser history and so on. Just don't use the registry cleaner or you'll mess up your programs and operating system.
You should avoid Registry Cleaners, Boosters, Optimizers, TuneUp Utilities... There is no need to clean the registry and this type of software will do a lot more harm than good. These utilities do not only remove what they think are orphan entries in the registry but legitimate items still in use will be deleted in the process, causing irreparable damage to some programs and the operating system.
Keep in mind that they will always find "errors" to fix, even on a fresh Windows install!
ccleaner is a decent program.even the registry cleaner.hasnt screwed up one machine i know of.the thing with registry cleaners is,they arent a magic wand that will make your computer run like a racehorse,but if you always backup your registry they cant hurt you.ccleaners registry cleaner is,however,the only one i would use.
CCleaner is so good I've seen it as an essential part of my Windows system for many years. But, that means it is also powerful, and if you play around with the settings, it could do serious damage. Since you need to ask the question, I would get it and use it only to delete files, and only those it deletes by default. The registry cleaner is good, but there is no point in using it. Registry is pretty good at cleaning itself and no fine tuning can have any detectable effect on computer speed - contrary to what many software vendors will tell you. Much better to leave the Registry alone. You can also disable startup programs. This is very useful, but I would leave it until you are sure you know what you are doing - although all your actions can be easily reversed so long as you don't delete the software. I generally disable startup entries, watch how it behaves for a couple of weeks, and then leave them disabled. Used just to keep your disk uncluttered, with default setting, CCleaner is safe and very effective. It will make your disk faster and reduce the need to defragment. I do this daily since modern browsers store an awful lot of junk.