Today, I tried again. Happily--the one occasion of happiness in this story--I didn't have to re-download the entire 60,000 KB; I only had to download the remainder. Cool beans! I t finished downloading in less than an hour, and I began the installation process.
About 3/4 of the way through installation, I got another error message telling me to insert the Word 2002 disk. I don't have a Word 2002 disk; Word 2002 was pre-installed on my computer. I have to press Cancel to make the message box go away. However, the Updates site informes me that Office 2003 SP #2 and something else were successfully installed; only Office 2003 SP #3 was not. I restarted the computer as instructed, but there is no change in the way Word is behaving. I still can't copy and paste from Yahoo Mail into Word. I haven't a clue why.
I am not particularly willing to shell out $$$ to buy a disk of Word 2002 when I already own the program, just to get one file.
I apparently also need to upload some sort of XP service pack, which is 67,000+ KB. Joy!
In the meantime, I am about ready to tear my hair out. If it's going to tell me to update, the least it could do is ALLOW me to update!