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When reformatting, Windows XP ask me to choose from these formatting methods. (Implying that ALL of them are "formatting methods"... even #3)

1. Reformat using NTFS (quick) 
2. Reformat using NTFS 
3. Leave the current file-system intact (no changes) 

What choice #3 really mean?

Does it mean:

A. Leave the current file-system (whatever file-system is already in use) 
and reformat to match that. (ie. If you current have NTFS, reformat to 
that again. If you currently have FAT32, reformat to that again. 
That is: Reformat without changing to a different file-system. 
Leave the current type.)


B. Do absolutely nothing. Don't format. 
Don't delete any of my files. Abort the formatting process entirely.
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It means install Windows on this partition without formatting it first. It will also ask you where it should place its "Windows"-folder since the C:\WINDOWS will still exist. It will simply continue on that disk without touching it.

Your data will still be there. It's explained here:

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It's what some support people call "Parallel Install" :) – Isxek Mar 11 '10 at 17:32
I didn't see anything about #3 on that link. #3 was the ONLY thing I needed to know about. – Margret Mar 12 '10 at 2:11

The answer is B. That option won't touch the drive at all.

That being said, if you're reinstalling, you're going to reinstall over top the existing installation. Remnants of the old system, malware/viruses, 3rd party tools that need to be reinstalled (now that your windows install blew away some registered component) can interfere with the operation of the new system.

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"The current filesystem" means "Don't format, rather just install Windows over top of the existing Windows installation there, keeping most of the registry, files, etc."

If you want a fresh install (which unfortunately is fairly useful when you run Windows), quickformat should be fine. On an old hard disk, you might want to use a full format, which will exercise the disk more, causing the hard drive to detect failing sectors and remap them automatically to special spare sectors set aside for that exact purpose.

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So how would I do "A"? Or is it impossible? The installer isn't smart enough to tell which file-system I ALREADY have... and just reformat using that same file-system? – Margret Mar 12 '10 at 2:14
You don't. FAT should die. Use NTFS. There is literally no reason I'm aware of to not use NTFS. – Alexander Burke Mar 12 '10 at 7:50

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