@Mor - It can cause permanent damage after a while if you don't change your habits. There are several things you can do if you want to take better care of your hands. Most people know that there are better keyboards that you can get, but there is also the choice of changing your original keyboard layout to one that's more friendly to your fingers. It can be confusing at first, but I've heard it's worth it in the end.
The best thing you can do, though, is try to stretch out your hands every now and then so that they aren't held in the same position all the time. There are plenty of guides to hand exercises online and you can look up other kinds of office exercises while you're at it.