Just for the record, I'm not an expert, but rather someone who has had some experience with this kind of problem. Try unplugging any unnecessary usb devices (Like phones or external drives) but keep the mouse and keyboard. Try using the computer for about an hour to see if there are any crashes. If there aren't any crashes, go one by one, replacing each usb device, and using the computer for around an hour, until you find the (possible) cause of you computer. Once you're found the device, go into your control panel and find the drivers for the device, and un install them, and proceed to reinstall them. IF your computer continues to crash, without any of the usb devices plugged in, you may need to replace the Hard Drive.