I have a PC with M/B Asus M3N78-VM, PSU Thermaltake TR2-420, 2x1 GB GEIL DDR2-800 RAM, AMD Athlon 64 x2 5600+, GPU MSI GeForce NX7600GT and I have a problem. When I turn on the PC, the HDD led is flashing repeatedly as the DVD-ROM. It's like they are looping in the turning on. The monitor shows nothing too. What can I do?