The reason your OS is unable to view any hard disk is because the drives you are using are perhaps SATA and you have not created any RAID.
Here is what you do:
Download the *ATA RAID Driver (for Windows Server 2003 32-bit, SE7501WV2 board) and follow the steps mentioned on the download page to provide RAID drivers for the OS to detect hard drives during installation.
This should solve your problem however you might just want to download Intel Server Management 5.5.7 for management of your motherboard and the related issues.
Also open it's READ ME.TXT and go through clause 8.
Additionally go through the following document for your own benefit.
Intel Go Green, Save The Environment!