The problem is that you're trying to install a service pack to Office XP, but you have Office 2007. Do not confuse the XP part in Office for referring to the operating system. Office and Windows have their own separate service packs, and so far as I know, Office 2007 is only at SP1 so far.
When I try to install the Office XP SP3 file, I keep getting a message that says the the "expected component was not found."
I don't know what this means, or why it came up. My software is a legitimate Windows version.
I have Win XP, home edition, 2 GB RAM, 240 GB hard drive, Office 2007.