You don't have to turn off the main switch connecting the PC to the electrical socket when your PC hangs or freezes. All you have to do is master reset your PC. These are the following steps to do it. Correct me if I am wrong because I am only a (student-12 year old)

Step 1)Try closing all your opened programs. If your computer responds by giving you this error message 'program name' not responding try by pressing and holding your keys 'CTRL+ALT+DELETE'. A popup window named 'Windows Tak Manager' will appear.

Step2)Go under the 'Applications' tab and try by highlighting the program that is not responding and click 'End Task'. If this does not work try repeating step 1 and go under processes.

Step3)Search for the program that is not responding and highlight the program, and then click 'End Process'.(WARNING:THIS MAY CAUSE SYSTEM INSTABILITY). (I DO NOT TAKE ANY RESPONSIBILITES OR LIABILITIES CAUSED ON ANYONE OR ANYTHING). Extensive overclocking may also be the cause of this.

Step4)If all the steps above do not work try by master resetting your PC by pressing and holding your 'Power Button' until your PC turn's off by itself, after this turn off the switch at the electrical socket and unplug the PC. Do not plug in the head and turn the PC back on wait until 10 seconds to let all moving parts in your PC come to a total stop and allow your PC to unload it's psysical memory (RAM). And then only turn the PC back on.

Weird la your problem, I have 3X 80GB Maxtor SATA 8MB Cache, 160GB Maxtor SATA2 16MB Cache all have been used for about 2 years plus but no problem. But the best I think is Western Digital because all the ones I use never corrupt before but my 40GB Maxtor IDE had a bad sector once. But it was bought in year 2002!.