Yes you can make a copy of your XP CD. To do that you will need third party
CD Burning software that has copying capabilities as XP's built in CD
Burning software cannot do this. There are many such commercial programs
such as Nero but there are good freeware alternatives. One excellent free
program is found here
http://www.cdburnerxp.se/features.php Just make sure
you use the CD Copy function to copy your original disk then put it away and
use the copy if you need it.
You also ask about making a full system backup to CDs. Once again you need
third party software. There are many such programs which are typically
called imaging software as they create an exact duplicate or "image" of the
system. This image can be compressed and spanned across multiple discs to
create a set. When you restore the image you will need all of the discs in
the set. Remember that a typical blank CD-R will only hold 700MB of data. If
your system has a large drive filled with data you might find that you need
many, many CDs to create the set. If even one of the discs in the set
becomes damaged then the restore will not complete. You will also find that
a restore may take many hours if you have many discs to keep swapping in and
out of a drive. A better solution for creating full system backups is to use
DVD's which can hold as much as 8.5GB of data if you have a Dual Layer DVD
burner and Dual Layer discs or 4.5 GB on a standard DVD Burner.
However, in my opinion, the best approach to full system backups is to use
an external hard drive. Hard drive enclosures are very inexpensive and you
can purchase very large hard drives quite inexpensively. An external drive
plugs into a USB port and you simply use the Imaging software to dump the
image to the usb drive. You can then safely remove the drive and store it in
another location, off site, until it is needed. This way if you have an
extreme problem such as house fire, disaster, robbery or such you backup is
safe to be loaded back.
I use Acronis TrueImage for this purpose. I have several hard drive
enclosures. I make periodic system backups and swap the drives around. It is
a simple routine to get into.