keychain cant store my Apple ID

hey I just got a MacBook from my cousin, and it won't let me sign into iCloud because there is an error message that continually says (and keeps interrupting whatever I'm doing even whenever the applications aren't opened,) "a keychain cannot be found to store "2030094579". and it give me two options: Cancel & Reset to Defaults. Cancel, doesn't do anything except make it pop up more and more frequently, and Reset to Defaults take me to another notice that gives me tow options: Cancel & Reset. Like before, cancel won't do anything and if I hit reset, I have to put in my login password. So I do that, and it tells me, "A keychain cannot be found to store 'c************@****l.com.'" and gives me two options: Cancel & Reset to defaults. We get the idea of cancelling at this point, so I hit Reset to Defaults. Which bring up Cancel and Reset. Reset requires my login password so I put it in, and tells me, "A keychain cannot be found to store 'c************@****l.com.'" and it does this absolutely useless cycle to no end, with no solution. I don't know what to do at this point.