Ok lets try this method:
run the live cd
open a terminal and enter:
sudo fdisk -l
this should give you an output something like this:
Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00023337
Device Boot Start End Blocks Id System
/dev/sda1 * 1 19202 154234880 83 Linux
/dev/sda2 19202 19458 2053121 5 Extended
/dev/sda5 19202 19458 2053120 82 Linux swap / Solaris
now the first entry above is in my system and shows as /dev/sda1 and it is marked as the boot partition by the little * in the column named "boot"
this is the partition we need to find on your system.
So whatever is listed with the little * in it is the name you need to use for the following command.
this should tell you that the device is not mounted, which is exactly what we want.
now you can enter the following:
sudo e2fsck -f -p -C0 /dev/as-you-entered-above
this will run a check on the file system and automatically repair any errors it finds.
Once it is finished,
type in :
there should be no errors.
once this is done ,shutdown the live cd and remove it from the drive then restart your computer.
If it does not boot first time, try tapping the "shift" key under the enter key from when you switch it on and get to the GRUB Boot Menu like yesterday, (the black and white screen)
Select the Ubuntu entry nearest the top with "RECOVERY MODE" written beside it and hit enter.
then use the arrow keys to select the "update grub bootloader" option and hit enter.
once this has completed select "resume normal boot from the menu and hit enter again.
the computer should reboot and start normally.