I have a computer which has a preloaded OS windows server 2003. Now i want to remove the OS and load a new server version. But whenever i try to do that the set up starts ans then it says Hard Dics not found. I want to completly get rid of the old OS and instal a new one. Hope i am clear. Please help me. Thanks.

The hard dics is SCSI Disc.I read one of rays answers on formatting. Accordingly i made a boot disc and booted the computer. But when i gave the command format c: the message appears drive invalid. Is it something to do with SCSI disc. Even when i tried to change the default drive to c , it says the drive in valid. My computer has two scsi hard drive. the poerating system is in the first disc. if possible help me. Is formatinf SCSI disc and reloading the OS somewhat complex than the normal. Thanks.

   I do not know anything about SCSI drives.  That is why I have not commented.
   Often SCSI drives are not recognized by boot discs.  I think that special drivers have to be included to recognize SCSI drives.

When you reload the o.s. you will have to have the drivers for the SCSI drive from the manufacturer on a floppy disk. Windows prompts you to press F6 to load the drivers so it will be able to access the disk.
Look on the disk manufacturers web site for a program to format the disk or it may be possible to format the disk during the installation process once you have loaded the SCSI drivers.