Keypress and what will happen then?

[trodas]

I do wonder, how hard is to change the program behaviour on keypress. I mean simple unpacked Win32 application. When I did not like the behaviour on, for example F1 keypress, it is possible to do something in ResourceHacker or similar to replace the "F1 keypess input" as to behave the same, when I hit F2 key, for example?
I just wonder how hard this is to do... Meaning - if I can do it. Or how hard is the input change on Win programs in general (Win2k)