Windows 7 - files left after reinstall

Asked By scbs29 on 10-Aug-12 08:58 AM
I have just wiped my hdd and done a clean install of XP Pro.
During the install I selected the option for a full hdd format.
After the install I was surprised to see in Documents and
Settings/../Local Settings/Applications two folders belonging to a
game that I had installed then uninstalled before the format and
install.
Surely a full hdd format should have removed these and left a clean
hdd ?
Can anyone advise ?
TIA

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Paul replied to scbs29 on 10-Aug-12 10:30 AM
What a format should do, is clear FATs or MFT, that kind of thing,
without actually having to visit each sector and overwrite the data.
When you overwrite the FAT, it effectively wipes out all of the
linkages to the clusters holding the data, the file names and
so on.

I would look carefully at the setup, like partition table, and see
if your old install is not still on there isomewhere. The partition
setup should give some idea what actual kind of install was done.

To give an example, I installed Win2K on a drive. Then, installed
it again. The second install, ended up in a logical partition,
rather than a primary, and one boot.ini file on the disk, controls
booting to either copy of the OS. So in that case, I'd be looking
in disk management, for the presence of a primary and a logical, as
proof the wrong thing happened at install time.

Some examples of the colorful display, available in Disk Management.
(Run diskmgmt.msc to see this). The second disk has three primaries
(the max), plus an extended, and the extended has two logicals defined
in it. If you install the same OS twice on the same disk, the second
install may be present as a logical.

http://www.techotopia.com/images/7/7c/Windows_server_2008_primary_and_extended_partitions.jpg

Now, if you had only a single primary partition, your C:, you can
also check to see if there are two OS folders. I am not sure, but
perhaps that is what happens, if you upgrade from one OS like
Win98, to a later OS. But then, I doubt the installer would
have "pretended" to be formatting anything.

For me, as a home user, installing OSes is like playing "Whack-A-Mole".
You install one, then get out the forensic tools, and see what happened.
And once in a while, you get a surprise...

*******

There are lots of neat ways to erase disks.

1) The IDE/SATA disks have a "Secure Erase" command in the command set.
Using the CMRR utility, you can issue one command to the disk, and
the disk erases everything. And the erasure command is remembered,
such that the erasure continues to run, if you happen to cycle the
power half way through. The advantage of Secure Erase, is once the
command is set, the drive only needs power to complete it.

2) There are tools like DBAN. DBAN will erase all the disks in the
computer, up to 99 of them at the same time. You unplug the disks
you do not want erased, for safety. Running a "single pass" erase,
saves time.

3) As a Linux user, you probably know about dd. This will erase a drive,
and presumably you would  do this from a Linux LiveCD, as your OS would
crash, if you erased the OS disk. Logically, this is as effective as
(1) at removing info. But there is a flavor of (1) that also erases
even the spared out sectors. A typical Linux setup will run this at
around 13MB/sec. Whereas (1) can do this at full disk rate (125MB/sec).
You can add parameters to this command, to make it run faster, but
the rate improves to around 39MB/sec or so. Still does not get up to
full disk rate. The main advantage of doing it this way, is not
having to read the CMRR documentation.

dd if=/dev/zero of=/dev/sda

Also note, that erasing disks in this way, while it leaves them
where the BIOS cannot tolerate an MBR which is full of zeros. The
BIOS will actually hang, and the computer will refuse to start. As
you can imagine, this requires creative thinking to fix... So if your
computer is very old, it might not like these options that much. If
you were doing (3), for safety you could put a single partition
on the drive after the cleaning operation is finished, in case your BIOS
is that finicky. Only one of my computers does this, but I
do not remember which one.

HTH,
Paul
scbs29 replied to Paul on 10-Aug-12 12:34 PM
snip

Thanks for the reply.
I had a look at my disks in Disk Management and in Paragon HDM 12
suite.
Both show both hdd,
Drive 0
Local |Disk (C:)  - NTFS - Healthy - (System)
Another pattion (E:) - NTFS  on the disk for storage.

Drive 1
Local Disk - Linux Ext4
Local Disk - Linux Swap2
Local Disk - Linux Ext4
NTFS disk (D:) - NTFS  for more storage.


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