I am having Windows XP installed on my computer that runs on Intel Core 2 Duo processor and Giga-byte motherboard. I also use a Sapphire HD 4650 1GB graphic card. I bought a new Seagate SATA-2 250GB hard drive as I was earlier only having 80 GB hard drive. Now when I have removed the old 80GB hard drive and installed Windows XP on it, the graphc card is not detected. Why is the graphic card not detected?