try upgrading all the drivers for hardware
it might be the HDD as said above
antiviruses arent all to relyable, so maybe reformatting your HDD will help
Maybe your OS is comflicting with new hardware
and unplug all unnecessaru USB devices at startup, then insert them one by one, and if just after you have plugged one in, your PC freezes, this means your device could be faulty or the USB port in your computer MOBO is faulty.
If it is this, just get a 4 way USB dock...