Last time I stated similar view re reg cleaners I got more disagreements. Strange world.
Aye, clean in an "emergency" only. CCleaner is probably more trustworthy than many if you must use one. But if in a state you think you need one you might consider backing all useful stuff off safe, and then formatting & reinstalling your PC operating system and applications from scratch.
PS if you are trying the "press here for a scan" offers rather than "download our free (or trial) app" type, then they tend to only claim (read exaggerate) loads of issues and try to sell you their solution.
why do you need it? unfortunately its often suggested by people who have limited knowledge of PCs to try and solve problems that have nothing to do with the registry.
re my question.
i have a very limited knowledge of computers and i kept getting phone ca a "technical department" telling me my computer is running slow and when i told them to stop ringing i was told that i was assisting hackers and they would have to take action against my computer. now my computer is even slower and i have tried system restore but no change.