Today I had to reboot my Linux machine for the first time in 280 days. Sniff, all that precious uptime reset back to 0 . Anyway, when starting up again there was an issue with the GRUB boot loader that simply stopped linux from even finding a harddrive to load from.

Disaster!

... Until I brought out my previously burnt GRML (http://grml.org/) rescue-cd, booted that into grub and got back into my system so I could get on internet to google on how to fix the actual problem. Everything now works as it should again (or rather, will be when I reboot the machine in a few hundred days).

The moral of this story is that you should prepare a rescue-cd so you can always get back into the system should things ever go south. Save the bootable the live-CD of your distribution; that usually has recovery tools on it. Or burn a dedicated system administration CD like GRML above. Do it before something happens. You will be glad you did.
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Griatch

Awesome advice! I think I should do this myself!

not exactly sure what a rescue cd is...obviously I am not a techie

If your system won't boot normally, a rescue-cd can be booted from instead. You can then boot into a stand-alone linux system (that runs off the cd) where you can get onto internet, investigate your harddrives and do many other things to fix whatever issue you had with your normal setup. In my case the system couldn't automatically find which harddrive to boot from, so the rescue cd helped me bootstrap this and help the system along.

There are custom linux distributions like GRML intended for things like this, or one can often use e.g. the Ubuntu live-CD for somewhat more limited fixes (but often more than enough).
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Griatch

You can also rescue files from Windows hard disks with Linux rescue-CD. There are ready-made .iso images for this purpose. Just burn them on CD with any proper CD/DVD burner app. Windows can trash itself to unbootable condition, this is neat way to correct problems or save data.

(Yes, I've have had in this situation...)

Good advice. Also, in my "collection" of printed documentation I have a copy of the steps needed to rescue an Ubuntu-based system under GRUB and GRUB2.

I use this one for years.
Has quite a lot of possibilities.
http://www.sysresccd.org/Download
Gerard.

That's an excellent idea, I'm booting up my Linux machine as i type. I'll do it right now. Thanks.

would be possible back up the OS including drivers software and all customization and reinstall from the back up?

Or reinstall on antother compatible computer (in this case obviously replacing a few drivers)

Yes. Search for remastersys (for Ubuntu/Mint/Debian). At one time it was available in the Mint romeo repositories but seems to be gone.

I still have a custom LiveCd that I made using remastersys of a Helena Isadora 32-bit installation that I liked very much.

Edit: Corrected version, after boot from it to verify the version...
Edit 2: PC, you may also be interested in this: LiveCd Customization [UbuntuWiki]

Remastersys looks really as what i was looking for thank Bob
and also the other link is quite useful...

i don't have problem to reformat and reinstall what i hate is have to reinstall all extra sw and customize again (i.e browser setting and add on, visualization preferences for file and so on and on

In linux, you should never, ever need to re-do your browser settings etc since such things are stored in your home directory - and your home directory should always, always in on its own partition. That one remains even if you reinstall the rest of the system.
Reinstalling software is another issue, but with Debian I find it an issue, it's so painless (takes some time but doesn't involve much real work).
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Griatch

Griatch, I'm not really familiar at all with the ins and outs of Debian; however, in Ubuntu and derivative distros the package manager can generate a list of installed packages, then after an "upgrade" or reinstall, you can reload this list into package manager and it will mark the packages for upgrade/installation. Nothing like this?

Also, about one year ago, I helped test a Firefox extension called Umarks [No longer developed/maintained] that would generate a list of installed packages and create a file that could be used to later reinstall the same packages in a fresh install. At the time it was quite useful as not many people had learned of the separate partions setup, and the distro upgrade would often break an otherwise working system.

That's a nice concept. Haven't tried it, but since apt can take any list of packages as input , I imagine a simple pipe to a text file would be enough to get a record. On the other hand, knowing Ubuntu is a derivative of Debian, there is probably an easy way to do this from an explicit command.
That said, I usually take a new install as a chance to weed out my program collection and go back to minimalism - it easily gets a bit sprawling after a while.
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Griatch

Sorry to hear you were lost there for a bit Griatch.
Glad to see you made it back though.