What you need is a resource viewer/editor, i.e. something like AATools but better (names escape me at the moment). I had a quick look and shell32 and winlogon.exe (in WINDOWS\system32) both have lots of common messages within, as will a few other files within this folder. The bad thing is, the likes of winlogon are used by windows so you can't overwrite it unless you boot to another OS, even then I'm not sure how a modified winlogon.exe file would even be taken by windows. 🙂 It's enough to get you going though.