i rebooted my desktop computer last night after attempting to install windows XP on another partition, xp made me restart and now the drive stops my machine from getting past POST, when i unplug the drive i can boot into a live CD, but if i try to hotplug the drive i get nothing, can someone please tell me how to recover the MBR of this disk so that i can use it again?

Hi,

You could change the boot order in the BIOS to the cd 1st then use the LiveCD to restore your bootloader. It seems that XP overwrote the bootloader. Hopefully you didn't format the whole drive.

BTW, M$ is notorious for this. You should install you M$ product first then your Linux. Backup all the systems so you can restore when problems of this type occur.

i know this, but the cd is the first boot device, POST fails, it doesn't get as far as a boot loader, when the HDD is plugged in i cant actually access the BIOS to change anything

Hi,

I assume the drive is a external USB or just a SATA on the buss.

Remove the drive. Then boot the 'LiveCD' and plug the hdd back after you have the system up. Check your logs to see if you have any errors or relevant information.

ok, i'll post the dmesg output in a minute

dmesg output does not change when i plug the drive in, the computer does not pick it up, just to clarify, this is an INTERNAL SATA 160GB HDD it is the only drive in the machine other than optical

also when i say POST i mean the Power On Self Test of the BIOS fails at detecting the HDD and hangs, it boots perfectly if the drive is disconnected

Hi,

How do you have the hdd configured in the BIOS? Do you see it while in the BIOS? Just curious as to how you have things configured in the BIOS? How do you have your drive configured in the BIOS with type and what about AHCI? Tried Legacy?

I thought your statement about the POST was that the system was failing. So the machine just doesn't detect it.

Which Livecd? What about passing parameters to the kernel at boot?

the machine detects it at post and hangs, it's an ubuntu 9.04 live cd, the drive is configured to S-ATA/P-ATA mode so that the bios prefers sata over pata, other options are PATA and SATA, i can only boot the machine past post if the drive is disconnected or sata mode is disabled

Hi,

Do you see the drive in the BIOS setup screen while it is plugged in?

How do you have the drive jumpers set on the drive? What is the hdd manufacture and model?

About finding the HDD...

If it POSTs...

I would try to burn a copy of PartedMagic 4.4 to see if it boots with the HDD present. PM 4.4 has Super Grub Disk for repair as a boot option . You might also try the latest SystemRescueCD.

If not...

I would also look to the interplay of the BIOS settings and how you have configured the HDD. As onebuck intimates, you can use the BIOS alternatives IDE/SATA/AHCI and the set-up configuration of the HDD to try to get the BIOS to co-operate with a live-cd to find the HDD. It is not supposed to disappear.

An advantage of using PartedMagic or SystemRescue is that, while playing with the BIOS and the HDD jumpers, you can use cheat codes to give yourself added variations, if that helps.

If I couldn't get either PM or SystemR to boot, I would try to set the BIOS to Fail-Safe Defaults and try again, changing the HDD to follow BIOS setting given under Fail-Safe.

I would be useful if you followed the querying admonition of the wise onebuck and supplied much more detailed information.

Depending on the motherboard chipset, you may have a motherboard that is sataI and a drive that is sataII. Most of the sataII drives have a jumper to set the drive to sataI. I have seen several Seagate drives behave similarly.

Guys, the thing doesnt boot if the drive is connected. Period, i cant boot it from anything!

Hi,

Since you don't seem to follow up with things that have been suggested and all you reply is that is doesn't see or boot. I'm out of here.

You've been given a lot of help but you don't provide detailed feedback for us to aid you.

Impatience...

If you want more advice on your problem, you need to tell us what are your equipment specifications and settings, what you tried, and what the result were.

If you are not more perseverant, neither you nor we will make much progress. onebuck had many useful suggestion for ways forward; try some.

In practice, I would pull the HDD so I could get into Setup and start to experiment with the BIOS, reinstalling the HDD to see if it is recognized by a live-cd. The HDD was recognized before, it should be again. However, there are several variables. Why it isn't is a bit of a mystery. There is no standard answer.