Administrator accounts have more safety functions in them in recent Windows versions, but you’re right… running as an administrator could be a risk.
run as administrator
It’s common not to get all of the information (such as the administrator password) with a used computer. There are a couple of approaches to taking ownership, but we start by understanding the risks.
Defragmenting a hard drive absolutely has its place. There are several ways to get to the controls in Windows XP.
Appdata roaming doesn’t mean your computer has been roaming. It’s nothing more than a folder designation on your machine. Why data may be put there, however, is a bit more complex.
If you have the password for the administrator account, you can easily elevate any other login account to have administrator privileges.