I assume this is Windows because I am not sure any other system uses such a thing.

I would have to ask why you are making changes to the registry. Unless you know what you are doing, making changes can cause the system to be completely inoperable.

What type of changes are you making? Malware can 're-infect' the registry each time the system is booted up. For example, the Run and RunOnce keys can be added to by malware, and unless you completely remove the malware, it will set itself to 'Load on Startup' using these keys at each bootup.

Really, I wouldn't touch the registry. Whatever problems you have, try and resolve them other ways.