I made a set of recovery CDs last year.  I understand that they
contain the information needed, in the event of a computer crash.  But
how does one replace personal files that were created since creating
the original recovery CD set. Compaq Windows XP allows only one set to
be created.
QUESTION:  How do people "Back-Up" their personal files, in a secure manner?

Yes, people who know, back it up.
As people entrust more and more crucial data to their personal hard
drive they become more and more dependent on it.
There is a plethora of backup programs--some are "stand-alone
professional grade", some are simpler components of multi-purpose
suites.
Be absolutely clear that a backup of your personal data to the same
hard drive as the original source, even a different partition on it,
provides very little protection.

Be organised in your file saving.
Save everything under My Documents in sub folders.
Consider moving 'my documents' to a separate partition.

Buy an external hard disk & use a synchronisation program to keep your
file backups up to date.

Regards,
Rick
http://www.websinstantly.com

Believe it, or not, I was thinking about movies I've seen where a
thief sticks a CD in and downloads information.  So...I stuck in a CD
and followed the directions and presto!  I copied my 'My Documents'
section.  Duh.

Thank you both.

Sub folders?

If you want a "secure manner", I would go one step further.  Make a
second copy using the movie thief method ;-) and either store it in a
safety deposit box or give it to someone you know and trust (if you do
this, offer to store a cd of theirs too that way you're both
protected).  The reason being, that if something bad should happen
like a house fire, there would be another copy somewhere else.

I'll definately make a second copy and ask a friend to hold onto it
for me.  What an excellent suggestion!  Thank you.

Another bit of info you might want to consider is to encrypt your
files with a password, and use high-quality encryption software.
Here's an article I wrote that deals with this issue:

http://www.andybrain.com/archive/unbreakable_encryption.htm

In your specific case, you'll want to probably back up your
information, compress it into one huge file by using Winzip or similar
methods, and then encrypt that big backup file.