Depends on which programming language you are using. I started out with C/C+ + and I have had to restart my PC many a time because of memory leaks. I don't think that messing some stuff up is hard in C. However, as long as one keeps away from vital parts of the OS, nothing will go wrong with the basic stuff. harryjames, you can also set up a virtual machine on your PC. That way you can break all you want in the OS and learn a bit about the underlying OS. If you want to start out with programming and later move on to a pi (which is great fun btw), I recommend creating a virtual machine with something like Linux Mint or Debian since these linux distros are similar to Raspbian (the default RPi OS).
Thanks for the advice! Unfortunatlely my pc isn't usable, and hasn't been turned on in a few years. Will maybe give it a chance to redeem itself.
Maybe just run linux directly on the PC then? Just for the heck of it :P