The first 3 Dell support technicians tried to persuade me to clean the temp files, to remove unnecessary startup programs and to reinstall Windows. It does not help if the computer complains an error during self test. I keep saying a self test error can not be solved by twisting the OS, but they won’t listen. After educating the representatives for a week I finally got one that has better experience (and better English) to examine my computer. A full system test shows bad sectors on the hard drive, and totally toasted the hard drive. Luckily I just bought the computer for 6 months so I asked for a replacement. Dell sent me one in 2 days and I sent back the broken one.
Now my back up hard drive started to fail … Time to call Seagate.