I have been experiencing this wird problem for quite some time. The thing is my system usually freezes at frequent intervels, right from booting. Sometimes the screen goes blank, and strange sounds appear to be coming out from hard disk. This can happen at any point of time while the system is running. When the windows has been loaded, and even some applications are running, suddenly the windows freezes, and the strange sounds return. The solution (which is a temporary one) is that I plug in- plug out my SATA 80 GB HDD, for some time (like 5-10 times, no limit as such), and the system or windows unfreezes and starts working properly, but the problem resurfaces again after 10 to 15 minutes... I want to know what exactly is this, as I have changed my HDD with the vendor, but the problem still exists with the new one too... HELP REQUIRED!!!