Not booting back for help!

[#1]

Hi ppl, back to get my ass saved again   Going away in the morning so trying to get the family computer running before I leave and hear nothing but twining until I get back   My computer won't boot up, I get the message

Quote

kernal panic not syncing unable to mount vfs on root fs unknown block 0.0

or words to that effect. How I ended up at that point was I updated yesterday then did a janitor clean using ubuntu tweak. I assume ubuntu tweak is safe to use, never had any problems with it before. Computer hasn't booted up since the missus tried this afternoon.
Can anyone steer me in the right start off direction towards a possible fix. Apologies for not doing my own leg work. If I had the time I would. Initial searches are people with new installs and mines an existing set up.
Running ubuntu 12.04 btw
Thank you.
Should probably add I don't have a 12.04 disc just at the minute but I have 10 something I could use for diagnostics, unless I need 12.04 in which case I need to download and burn one sharpish.

[#2]

I have a copy of 12.04 just dug out of a draw but it doesn't seem to be able to run from the CD. I can run the 9.10 disc I have and it shows the hard drive is functioning. If that's any help.

[#3]

Have you tried an older kernel from the list supplied by GRUB?

[#4]

Hello again mate, spent a few hours on it last night but couldn't get it sorted before I left. Now that I've had a proper look at the situation I seem to have a non functioning kernel and have deleted all the others. School boy error deleting old kernels before testing the new one. Maybe the new one is ok buit since using ubuntu tweak I may have cleared out some system files that were needed before I rebooted! Is there a way of re-installing the kernal if I boot from the 12.04 cd?

[#5]

This http://askubuntu.com/questions/41930/kernel-panic-not-syncing-vfs-unable-to-mount-root-fs-on-unknown... might help

[#6]

Thanks for the link ill give it a try when I get back. Watch this space! Another thing I may hjave messed up with my fumbling was while trying to repair the grub I used 12.04 cd in repair mode but I may have installed it on the wrong drive. I have two on ext4 is there anyway of checking? I also downloaded another copy of 12.04, mine was alternate and wouldn't boot to live cd for some reason. My copy of 9.10 was no problem. Does it matter which version I try to achieve this with?

[#7]

It probably doesn't matter which version you use , it just needs to be a Live CD. However I'm not sure about the level of support for EXT4 in earlier versions...

[#8]

Ext 4 support has been around for a few years.  The alternate CD WILL NOT BOOT, is is designed as an update media. You need the live cd version.
You could try booting from what you have and doing a chroot on it. Google it for a better explanation, then do an update while in the chroot.

[#9]

Cheers guys. I'm away for 5 or 6 days so will have a shott when I get back. The missus and daughter will just have to live in 1980's for a while. Won't do them any harm. Not sure what version of 12.04 I downloaded, maybe was the live cd went to bed before I had time to burn it. If I remember right I had problems installing originally which was solved by using alternate. Ill let you know how I get on with chroot.

[#10]

I've been looking into chroot and unfortunately I'm not sure what my next move would be. Once I boot up with the live CD what would be my next move for restoring my machine to a working system. I think what I'm trying to do is update the current install and repair anything that is broken.

[#11]

If you boot from a cd then chroot to the system you are then working on the original system not the cd. You you can pull an update down or reset grub or WHY.

[#12]

I'm running the 6.10 cd. So how do I go about chroot into the system and getting the update?

[#13]

I don't know if 6.10 will be any use for recognizing Ext-4 partitions, I thought Ext-4 support started around 9.04 ?

[#14]

apologies I mean 9.10, was typing from my mobile but now using the live cd. Seems like so many ways to do this chroot thing I'm not sure if I'm making things better or worse at the minute by trying!

[#15]

You got me worried there, as I HAVE been known to use 6.04 and 6.10 to get systems started, as later versions had booting issues with certain DVD drives which could be overcome by starting from the 6.xx versions !