its not coz of Zone Alarm..
This error occurs when the partition marked as active does not contain the operating system boot files. The partition for the OS must b a primary partition that has been marked as active. If it is a SCSI, SATA or RAID drive the appropriate drivers need to have already been installed. The boot partition must be located on the disk pointed to in the BIOS boot sequence. The below advice is for single boot systems. Some exceptions apply if you have a dual boot setup......
So, two issues:
1. Having the PC boot from the correct drive, properly partitioned with the boot partition set as "Active".
2. Having the right files in that partition.
You can change the active partition using fdisk. And you can change the first boot device (but using an optical drive with a Windows CD to boot from can cause you problems later) in the BIOS.
Using fdisk:
1. Boot to a command prompt by using a boot disk (if you have one. Otherwise you can make one from any Windows 95/98/ME PC.
2. At the command prompt, type fdisk, and then press enter.
3. Click set active partition, choose the partition that you want to make active, and then hit enter.
4. Press Esc.
5. Remove the boot floppy disk, restart the computer.
also then...
1. Start your computer by using the Windows XP Setup floppy disks or by using the Windows XP CD-ROM.
2. At the "Welcome to Setup" screen, press F10, or press R to repair.
3. Press C to start the Recovery Console.
4. Copy the Ntldr file from the Windows XP CD-ROM to the root of your system partition by using the following commands, pressing ENTER after each command:
1. Type cd .. to go to the root of drive C. (Note the space)
2. Type the letter of the CD-ROM drive
3. Type cd i386 to change into the right directory
4. Type Copy ntldr c:
5. Type Exit
also i searched microsoft and got sum help.. refer below..
*www.microsoft.com/resources/docume...Windows/XP/all/reskit/en-us/prkd_tro_bohs.asp