I just did everything DaltonST said, short of reinstalling Calibre. Gave up in the end
I think I'll just use Calibre on my desktop (and sync my Kindle from there). Thanks for the help everyone!
PS: Would you guys think it has something to do with the CPU I'm running? Because it's a very new CPU, the Intel Pentium Silver N5000. Apart from that and the touch screen (it is a Yoga, after all), I can't think of anything else that would cause the issue.
- Ming