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.
whenever i make changes to my registry and restart my computer it always resets to default registry settings. does anybody know why this is and how to fix it?