I am rebuilding a Sony Vaio VGC-RC110G Desktop. Once i get to the point where i can create/delte partitions (booting from an XP PRO CD) it gives me 4 messages saying Unknown Disk (There is not disk in this Drive.) I have determined that those are the Media Readers attached to the pc. BUT, i do not see the primary drive AT ALL. SATA 250GB. Any ideas?