The computer hangs for a few seconds and then runs again?

Hi everybody,

My recent 2 days of continuous computer crashes constantly, whether it is web or movie on the hard drive, it hangs for 10 seconds to 30 seconds then release again. , but after nearly a minute of running back to the phenomenon of crashes temporarily for about 20 seconds to run again but hang. I tried unplugging the VGA card and the RAM was cleaned but it did not fix the problem, the crashes have happened before but it hangs is always hanging and not released to run like now, before i also machine cleaning and crash dead hard this machine was thought to have been processed. You let me ask this error can be due to any device, right now while asking this question I also have to stop a few seconds to complete this question, which is quite frustrating and urgent Friends for their opinions .

Thanks so much!