Unsolved Mystery-The driver detected a controller error on \Device\Harddisk

Download and run Belarc Advisor for a comprehensive printout of you system as it is. Then do a device manager investigation via control panel/system to establish an information base. Do Alt-Screen printouts of each display and paste to wordpad w/save-as to a dtg name in a convenient folder. After an error message or crash recovery rerun the device manager investigation and compare with base printouts for differences. Tedious but usually effective in locating problem areas. The slowing down sound you mention may be a symptom of pending power supply failure or an overload either of which could effect (cause) your original problem.