recover centos 6.2 after installing windows8

[mahdi]

Hi everyone.
after recovery Centos I got a big problem.
when I type command in rescue shell my external HDD was conected and I run this command "grub-install /dev/sdb1" several time and now the HDD dosent recognized in centos and known as unknown device. and this problem also happened to other partition on my internal drive.
Can I fix it?
My data lost? all of them? :-(

[pschaff]

[quote]
mahdi wrote:
Windows 8 dosent exist on boot menu and I not able to boot Windows 8 any way.
what can I do?[/quote]
Is there not an entry "Other"? If so, that is Windows. You may want to edit /boot/grub/grub.conf to use a more descriptive title.

If not see Grub Installation for CentOS 5 and 6.

If still confused, show the current contents of /boot/grub/grub.conf and [url=http://www.centos.org/modules/newbb/viewtopic.php?topic_id=28723&forum=54]provide more information about your system[/url] by running "./getinfo.sh disk" and showing us the output file. This may also help with the external drive issue if it is connected.

[mahdi]

unfortunately my windows partition also dont known in centos and like my external HDD dont recognize as a partition.
In disk utility its known as a unknown partition.
what can I do?
I also run the [i][b]fdisk -l[/b][/i] and got this

[i][b]Disk /dev/sda: 250.1 GB, 250058268160 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xc96b2927

Device----Boot---Start-----End------Blocks-------Id----System
/dev/sda1-----------1------5737------46080000---83----Linux
/dev/sda2----------5737----5992-----2048000 ----82----Linux swap / Solaris
Partition 2 does not end on cylinder boundary.
/dev/sda3----*-----5992-----6037-----358400--- 7---- HPFS/NTFS
/dev/sda4----------6037------9817----30361600---7---- HPFS/NTFS
[/b][/i]

but it dosent exist in Computer on Centos.
I also run the [i][b]grub-install /dev/sda3[/b][/i] and [i][b]grub-install /dev/sda4 [/b][/i]on the rescue shell.

[pschaff]

What are you trying to accomplish by running grub-install on random partitions, such as your Windows NTFS partitions? It can't help anything and may be causing damage.

You still have not shown grub.conf, or anything about the external disk.

[mahdi]

I connect my external HDD to another computer by windows.
In that computer my external HDD show as a partition in my computer but when I double click on it it say to format the device.
In the Disk Managment the hard show correctly and has an active partition.

[pschaff]

Was the external hard disk formatted as NTFS? If so Windows probably did not take kindly to having grub boot code placed in its boot record. I'd try installing ntfs-3g following [url=http://wiki.centos.org/TipsAndTricks/NTFS]TipsAndTricks/NTFS[/url] and see if CentOS will mount it. You seem to have very little to lose by trying.

You may also want to try a google on [url=https://www.google.com/search?q=NTFS+recovery+linux+tools&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:unofficial&client=firefox-a]NTFS recovery Linux tools[/url].

[mahdi]

I install these pakage befor and now I can mount any NTFS device like Flash drive, but My HDD dosnt work.
I think because I try to install grub boot loader to HDD and now it dosent work.
Is there any way to fix it?

[pschaff]

Did you try the google search recommended in my last post?

[YBellefeuille]

[quote]
Device----Boot---Start-----End------Blocks-------Id----System
/dev/sda1-----------1------5737------46080000---83----Linux
/dev/sda2----------5737----5992-----2048000 ----82----Linux swap / Solaris
Partition 2 does not end on cylinder boundary.
/dev/sda3----*-----5992-----6037-----358400--- 7---- HPFS/NTFS
/dev/sda4----------6037------9817----30361600---7---- HPFS/NTFS
[/quote]

There's a problem here; your partitions seem to overlap. Partition 1 should start on cylinder 1 and end on cylinder 5737; partition 2 should start on cylinder 573[b]8[/b], not 5737, and so on.

(I realize that partitions can begin and end in the middle of a cylinder, but then why does the warning "Partition 2 does not end on cylinder boundary" only appear for partition 2?)

To make sure, let's see the partition limits in blocks, not in cylinders. Please do [b]fdisk -lu /dev/sda[/b] and post the results.

Did you create the partitions yourself using [b]fdisk[/b], or did the installation program do it automatically?