hello My PC was crashing erratically, often while I was using Photoshop, several months ago. I replaced a broken fan and later plugged in a loose cable (temp LCD display). It's begun crashing again. A shrill two tone alarm sounds and the computer continues running for a few minutes, long enough for me to shut her down. Or a lower pitch two tone alarm sounds accompanied by the system shutting down completely. My specs: AMD Athlon XP 2400 2 GHz; 512 Mb RAM Power supply: Turbolink switching power supply LC-A350ATX (350W) ABIT-Nf7 motherboard CD burner DVD burner (self installed) The temp never goes over ~84F on the display. I've reformated, reinstalled windows. Could the power supply be too low? Is the motherboard failing? Overheating? Any ideas about what's sounding the alarm?