Don't know y Restore the OS to factory default. It is OK now. THanks.
Uninstalled USB driver, MS security essential, rebooted and the usb device working fine, BSOD problem still exist. found the resolution changed...
Lenovo X220 with 64-bit Windows 7. Symptom: always hanging up with blue screen. Minidump log Opened log file 'D:debuglog.txt'...
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