The best advice people are saying about retrieving some data from the system to which it won’t boot is:
On a Laptop often you have to disassemble the computer to remove the battery or jump the CMOS reset. On some laptop, like many Dells, and Think Pads the battery can be accessed from one of the slots at the bottom, and it is located deep at one side of the slot.
More commonly battery is located on lower side of the motherboard, and to access it you will have to remove the motherboard.
Before disassembling remove battery and unplug the AC adapter.
Do not short any pins unless you are sure that you are jumping the CMOS reset pins, even without main laptop battery you can still damage components touching here and there.
The best way to erase CMOS is removing the laptop battery for one minute, and then putting it back.
This will reset CMOS to factory and erase BIOS settings.
The other remedy is:
When you cannot boot up your computer, just purchase a live CD of a Linux Disc, any live CD will work, (Koppix, Open Suse, Ubuntu, Fedora, etc…) This will bring up a working Operating System, which will allow you to get your files off of the computer and then you can recover the system.
Using the UBUNTU Live CD for Booting
What we are going to do is use an Ubuntu LiveCD to boot up the dead Windows computer from the CD room drive. Once the dead windows computer is booted up, you can then copy your data files to a jump drive, or even across a network to a server, or another computer.
What you need is another computer, and downloads an ISO image of Ubuntu. Just in case you don’t know what Ubuntu is, I highly suggest that you look into it. It’s a free operating system that is much more stable than any windows operating system.Now to copy an ISO image to a CD, you don’t just copy it over there. Rather there is a particular way you have to make the LiveCD in order for it to be bootable.
Once you have made your Ubuntu LiveCD, go into the BIOS of your dead windows computer, and make sure that the CD room is set to the first bootable device. Select the option Try Ubuntu without any change to your computer and your dead computer will boot up in Ubuntu. It will take a little while, but be patient, as you are booting from a CD. After the computer has booted up, in the upper left corner is a menu bar. Click on Places then on Computer.
Cheers:p