Really screwed up!

[Wise Acre]

I'm trying all of your recommends to see if I can get this thing back on track. I called Lenovo customer disservice, and asked them how to restore the BIOS, but their response was that the motherboard was damaged, and there's nothing that they could do to help. Typical!

Okay, so while I was writing up this response, I was also trying to reinstall from a usb thumb drive. Nothing... It didn't even recognize that there was a drive attached to the computer.
What exactly am I looking for with fdisk -l?

[Wise Acre]

Can anyone translate this into english? I got this from https://wiki.centos.org/HowTos/InstallFromUSBkey. Am I supposed to do this on a different computer than the one I'm trying to fix, or the Lenovo?


Partition the USB key into two partitions: the first, FAT32, and about 250M; the second, the rest of the drive, and ext3. (An ext3 partition is required because the ISO file, that will later be copied to it, is larger than the maximum file size for a FAT32 or VFAT partition.)
Mount DVD1, if it isn't automounted (on /media, or /mnt). The following assumes /mnt/USB and /mnt/DVD.

Mount the USB key on /mnt/USB/.

Copy the directory and contents of /mnt/DVD/isolinux to /mnt/USB/.

Rename /mnt/USB/isolinux to /mnt/USB/syslinux

Rename /mnt/USB/syslinux/isolinux.cfg to /mnt/USB/syslinux/syslinux.cfg

Copy the directory and contents of /mnt/DVD/images to /mnt/USB/. (A bug has been filed [ToDo - add link] because as of 11 Jan 2012, the install requires the .iso (see below), but linux rescue requires the contents of images to load and run.)
Assuming that the USB key is /dev/sdb

syslinux /dev/sdb1

Unmount the first USB partition, and mount the second

umount /mnt/USB
mount /dev/sdb2 /mnt/USB

Copy the .iso file to /mnt/USB. Do not use the LiveCD or LiveDVD. Use DVD1, the minimal CD ISO, or a combined DVD1/DVD2 created following CD to DVD Media. Do not copy the contents - the install now wants the .iso file itself, which it mounts during installation, and follow the upstream Installation_Guide to create an images directory on the same partition. Optionally, add DVD2 if you used DVD1, and need it for the install.

Optional: On /mnt/USB, create a grub.conf. This may be required if your system wants the USB key as the first drive, so that you can later copy it to the hard disk. See HowTos/GrubInstallation section 2 for guidance.
Umount the USB key, and it's ready to use.
Boot from the USB media by setting it as the first BIOS boot device, or on some BIOSs by hitting a key such as F12 to select a boot device after POST.

During the installation process, the user is asked "What type of media contains the installation image?" Select the first partition on the USB key, which should appear in the menu under "Hard drive", then /dev/sda1 or whatever device corresponds to the first USB partition.
After partitioning, the user is asked whether to install the Grub boot loader and where to install it. After booting from the USB key, the BIOS may think that the USB key is the first drive. If the USB is seen as the first device, then to install the Grub boot loader on the hard drive MBR, which is the usual case, the user must change the order of the hard drives using the Grub advanced installation options.

After the Grub installation options, the following error message may appear: "Missing ISO 9660 image: The installer has tried to mount image #1, but cannot find it on the hard drive". The installation program is looking for the ISO file on the first partition of the USB key, but it's on the second partition. Go to a terminal with a shell with Ctrl-Alt-F2, unmount the first partition of the USB

umount /mnt/isodir

mount the second partition on the USB device. This will be the same device used in #14 above - for example

mount -t ext3 /dev/sda2 /mnt/isodir

Return to the installation program (Ctrl-Alt-F6) and choose "Retry".

Finish the installation and reboot without the USB device connected. If there are problems booting then it is likely the boot record was written to the wrong device. See How to re-install bootstrap code (GRUB), and if having difficulties determining the correct device, Troubleshooting GRUB Issues.

[TrevorH]

Ignore all that, it's from the section lower down where it says "there are also other older methods".

The correct way to write the iso image to a USB stick is just to dd to it. So if you insert your USB stick and it shows up as /dev/sdX then you run

Code: Select all

dd if=/CentOS-latest-DVD.iso of=/dev/sdX

and that's all that's needed.