Ran CCleaner Registry Cleanup

notEcho, since I do not know what you have installed and uninstalled, I cannot give you advice on what is safe to delete or not. This is the rule of thumb: If you are not 100% sure, DO NOT delete it. Leaving the keys there, even if they are obsolete, will not slow your system down one nanosecond. You do not have to worry about the registry with Win 7. If you know that one of these keys you listed is referring to a program you have uninstalled and that it refers to nothing else, it is safe to delete it.

Yeah, you should be fine. Some of them will come back though, i.e .net framework 1.0, unused file extensions, etc. Just make your backup and keep it for awhile, but you should be alright from the ones I see.

If you are concerned then you can back up the deleted Reg keys which can later be "merged" from the file to replace them.

I stopped doing this because it in ten years time it has never given me registry problem.

Remember, besides deleting the bloatware to uncheck everything in msconfig>Startup except AV and gadgets as the others are freeloaders on your RAM/CPU and can spy on you. Use a lightweight free AV like MS Security Essentials. Use the built-in Win7 utilties instead of duplicative factory versions.

Well, I wouldn't say it doesn't make any mistakes.

A few versions ago, awhile back - it would pick up and delete (if you ran the registry cleaner) the "Turn on Bitlocker" key from a drives' right click context menu. Although that case wasn't a big deal, it still wasn't proper. Myself, I wouldn't exactly call it infallible.