If Linux can't mount the hard disk, my guess is that either the motherboard or the hard disk has gone south.
I'd take the hard disk out, put it in an external enclosure and see if you can get to your files on another PC. You might need to take ownership if you run Windows on that other PC, but that's easy. And if you boot from Linux on that other PC you don't even need to do that.
But, of course, from a broken hard disk you might not be able to get all your files and possibly even none at all. That's why most people back up BEFORE the disk breaks down. Doing it later is quite uncommon, and possibly quite expensive if you have to find a data recovery company to do it for you. Than you NEED to pay.
Kees
any knowledge or help for a novice would be greatly appreciated. I have some files which I NEED to back up before reloading an OS Laptop running XP (I think Home SP3 but not sure) went belly up during java update which was not supportive of XP. Now Have hal.dll missing or corrupt error. Can only source XP pro disc. Can boot from cd and access recovery console. Will not expand hal.dl file from cd. Tried chkdsk but this remains on 0% complete for >1hr so I'm assuming its not working. I have tried a Linux program but it cannot mount the HDD. Is there anything I can try before admitting defeat Chefs in advance Colin

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic