Ok, I looked almost everywhere to find a solution for my prob but with no success.
I'm having a problem with Windows 2000 not starting up ??!! It either gets stuck "freezes" at the splash screen or it gets stuck while performing the Check Disk at startup and never gets through that. A friend recommended to have the graphic card changed which I did, but same thing.Then someone suggested to format the PC which again I did but "Partially",coz I have 2 partitions C: & D:. I didn't want to completely format the HDD as I have plenty of "Important" documents in D:.
Can someone tell me how to get rid of this prob without loosing the information in D:.
and get the Damn thing running normally again.. PLEEEAAASSSEEE ...

Presuming it booted fine before, Usually "won't boot" is caused by something changed so is there anything at all you changed, installed, removed, etc.? Otherwise often caused by hardware failures. Stopping during checkdisk could indicate drive or controller failure but i don't it myself.
As you say you have important data i would first backup the data before trying ANYTHING. Have you booted with the win2000 CD and tried reovery?

Ok, I managed to transfer most of the data to another computer and I clean format the PC.I deleted both partitions and created 2 new partitions "BUT" I still have the same problem it just gets stuck and all I can do is press the reset button to restart the PC.

Can someone PLEASE tell me how to fix it ..

You did a fresh install of Win 2K? Not a restore of any kind? Did you try booting from the cd and do a recovery? Could you give a brief description of the hardware and what kind of partitions (ntfs, fat, etc.) Also try setting the video to basic VGA and see if that helps.