Hi,
Can you start in safe mode?
If you can try SFC. Sometimes, some of the windows protected files can be lost or changed. To detect any problems run the program “System File Checker” (SFC). Before you run it you should purge your PC’s cache:-

Go to “START”
Click “RUN”
Type or “copy and paste”.. sfc.exe /purgecache

Note:- the space after “exe”.

The “purgecache” in this command will empty the cache before you run the file checker. You should always purge the cache before scanning with the System File Checker (SFC). That way, you can be sure that system files are copied from your Windows installation media, and are not infected with malware or corrupted. After the cache has been purged, run System File Checker.

Go to “START”
Click “RUN”
Type or “copy and paste”… sfc.exe /scannow

Note:- the space after “exe”. You may be required to use your installation disk.

This could take a long time to complete, when finished, reboot and see if the problem still exists.

cant boot on safe mode
same message comes

Hi again,
This one is from Microsoft.....
1. Configure the computer to start from the CD-ROM or DVD-ROM drive. For information about how to do this, see your computer documentation, or contact your computer manufacturer.
2. Insert the Windows XP CD-ROM into your CD-ROM or DVD-ROM drive, and then restart your computer.
3. When you receive the "Press any key to boot from CD" message, press a key to start your computer from the Windows XP CD-ROM.
4. When you receive the "Welcome to Setup" message, press R to start the Recovery Console.
5. If you have a dual-boot or multiple-boot computer, select the installation that you have to use from the Recovery Console.
6. When you are prompted, type the administrator password, and then press ENTER.
7. At the command prompt, type bootcfg /list, and then press ENTER. The entries in your current Boot.ini file appear on the screen.
8. At the command prompt, type bootcfg /rebuild, and then press ENTER. This command scans the hard disks of the computer for Windows XP, Microsoft Windows 2000, or Microsoft Windows NT installations, and then displays the results. Follow the instructions that appear on the screen to add the Windows installations to the Boot.ini file. For example, follow these steps to add a Windows XP installation to the Boot.ini file:

i inserted cd into drive n den restarted
but at restarting d same old error message comes

Hi again,
Try removing your motherboard battery for a few minutes, replace and reset BOIS, and reboot to OS CD and see how it goes

did you make this change first
'1. Configure the computer to start from the CD-ROM or DVD-ROM drive. For information about how to do this, see your computer documentation, or contact your computer manufacturer. "

its usually done by going into the bios/setup, and change in boot order
'