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Should I reinstall Windows from a fresh boot, or by running the installer from within Windows?


I need to repair my Win XP Pro SP2. I lost my original install CD so I
bought another new, never registered, full install CD with SP2. From what I’ve
read, there are two methods: 1) Fixing from a fresh boot and, 2) Starting from
within Windows.

This question actually turned into a series of related questions regarding
the two options, so let’s take a look at some of the nuances of installing a
new copy of Windows XP.

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The questioner continues:

Option 1 basically says to insert the CD, turn on the PC, press any key to
boot from CD, press enter to select “setting up Windows XP”, press F8 to accept
EULA, select the drive to be repaired, press R, reboot from the hard drive,
then follow any additional prompts.

1: After pressing R, will there be some kind of prompt asking how I want to
reboot or do I have to be psychic and know when to remove the install CD so it
boots from the hard drive?

Well, it always helps to be psychic, but fortunately, you won’t need to be
for this. Depending on where in the process you are, Windows setup is actually
smart enough to know what to do. it will typically will “do the right thing”
even if the CD is left in the drive. If there’s any question, it will simply
instruct you to remove the CD.

2: I have to modify my BIOS so it boots from CD. How will I be able to boot
from hard drive without re-modifying the BIOS?

“.. it always helps to be psychic, but fortunately, you
won’t need to be for this.”

Modifying the BIOS doesn’t remove your ability to boot from the hard disk,
it simply adds the ability to boot from CD.

The common, and default boot sequence is:

  • Look for a floppy disk – if one is inserted, stop looking and try to boot
    from that.

  • Look for a hard disk – if one is found, stop looking and try to boot from

The common change is simply to add the CD-ROM to that list:

  • Look for a floppy disk – if one is inserted, stop looking and try to boot
    from that.

  • Look for a CD – if one is inserted and can be booted from, stop looking and
    boot from that.

  • Look for a hard disk – if one is found, stop looking and try to boot from

What you boot from is controlled simply by what’s inserted.

3: Is the install CD ever removed during the process or will there be a
prompt at the end to remove it?

Windows install will, in all likelihood, ask you to remove the CD at some
point. Possibly at the end, but quite possibly in the middle instead, if it
performs an intermediate reboot.

The second method usually says to insert the CD while Windows is running and
look for a screen asking what you want to do. Then click the arrow next to
install XP, choose to perform a new installation, accept the EULA, enter
product key, keep clicking Next until you get to a screen called Get Updated
Setup Files, select no to skip downloading setup files. Eventually, the
computer will reboot and it should reboot from the hard drive, not the CD. More
prompts, select Setup XP Now (do not choose to repair with Recovery Console),
accept EULA again, and select the drive to be repaired and press R.

4: Same as first. How do I choose between rebooting from the hard drive vs.
the CD?

And as before, Windows Setup is also smart enough to know when it’s part-way
through a setup process, and will either “do the right thing” regardless of
whether the CD is in the drive, or it will ask you to remove the CD.

5: Since the XP on my system doesn’t have the same Product Key that is on
the new install CD, can I even use Option 1 since it never asks for the Product

That’s actually a pretty good question, as product keys and the legalities
of all this are pretty mysterious.

If your original copy of Windows was legal, then leaving the existing
product key in place should be just fine. In this case, your new copy of XP is
actually an additional copy – you could install it on a second machine
if you like.

If the original was not legal, and you want to legalize it, you can simply
update the product key using various tools available. A Google search of
“update windows product key” found several, including this one: Windows XP Product Key Modifier.
Caveat: I’ve never used it, so I can’t speak to how good this
specific tool is but it appears to do what’s needed.

If you install from scratch, you’ll be asked to enter your product key. If
that old one was legal, you could enter it, or the one that came with your new

6: Will the Microsoft validation scan recognize my computer with a new
Product Code? Do I need to alert them in any way or provide proof of ownership
of the new install CD?

You don’t need to do anything unless your system asks you to.

For a full install, Windows Product Activation (WPA) will be required, which
will take care of all that. For a re-install or repair, WPA may, or may not, be
required, depending on what Windows Setup sees. I’d be surprised if it did, but
even if it did, WPA is quick and painless, if your copy is legal.

Thanks for your help. I read the Microsoft KB articles and they left me in a
daze. It was like reading a foreign language!

Welcome to my world. Some days it seems I’m less of an answer guy, and more
of an interpreter.

Whatever works. :-)

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4 comments on “Should I reinstall Windows from a fresh boot, or by running the installer from within Windows?”

  1. Don’t re-install Windows! Install Ubuntu! Install Gentoo! Install Debian!

    Wait, this isn’t Slashdot.


  2. On the product keys:
    The Old One may not work with the new CD; Windows is picky about using OEM-keys (ie, the one from a Dell or whatever) versus Retail-Keys.

    So make sure you have both on hand!

  3. I had an issue with my Windows XP Media Center Edition 2005, so I got the installation CD that came with the computer, and I used the “update” to hopefully fix my issue. I found later that the issue is not my operating system but something else. However, ever since I ran the “update” with the reinstallation cd, during the boot up sequence, the computer selects the xp professional edition (which is not installed on my computer) unless I select the xp home edition within 2 seconds. How can I get rid of this nusance? I tried msconfig and selected in the boot.ini xp home edition as a default, which solves the problem , but I’d like to delete the xp professional boot sequence if I can. how do I do that?

  4. my cpu won’t boot, says wint\system32\drivers\ missing or corrupted. i’m using a compaq evo. when i install the recovery console for windows xp home edition, the system keeps asking for the windows xp home edition cd rom to be installed. i’ve downloaded 2 different windows xp reinstallation discs and tried to reinstall the program with no success. what can i do at this point short of taking it to a repair facility.


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