John is correct about making sure it's turned off properly if you have a mechanical hard drive. I would also take note on how the hard drive is positioned inside the case. Sometimes drives are mounted "sideways" instead of horizontal. If that's the case, secure your computer tower on its side so that the hard drive is laying flat. This is because if it's sideways, a good bump can move it out of its parked position and damage the disk.
Hopefully you have solid state drives (SSD), and if not, it might be best to invest in them. They are quite a bit more expensive, but they can't be damaged as easily with bumps and vibrations because they don't have moving parts.
If you have any PCI cards inside, I would also open the case and ensure that all the screws that hold the PCI cards (video cards, sound cards etc) are tight. I've always built my own PC's and find that sometimes a short car ride can loosen already loose screws.