Shoutbox

It isn't a matter of running or not. It's more a matter of running 100% correctly.

I'm no programmer of MSN Messenger, but I do know that in general many API's and other programming stuff depend on the OS it was designed for. eg: many API's do not function on other OS's or are simply stubs or behave a tick differently. This means you wont get an error, but the function wont do anything either or output something slightly different. This goes for many stuff (the very much used LoadImage and LoadIcon API's are a perfect example of that; if used in a certain way they behave a very small bit differently on different OS's, so small you wont notice at first, but in the end can cause serious errors).

If a program _seems_ to be running on another OS, it doesn't mean it works perfectly 100% without any glitch. Glitches can even be very small, so small you wont notice at first or only notice in certain circumstances.

If MS desided 7.5 is XP only, then there are perfect reasons for that. They do not limit a program to a certain OS just for the fun of it. And they also do no limit something to XP, while it would perfectly run on another OS, just because they want people to upgrade their OS, that's also nonsense.

Instead of asking me how do I know it wont run perfectly on anything other than XP, the question should be how do those other people know it _does_ run on another OS... Do those people magically know the exact code of MSN Messenger? Do they have the source? No... You'll find that those people wouldn't be able to provide a perfectly solid technical explaination for it; they have no proof what-so-ever; they're just guessing (or repeating what others say); they just _think_ it runs perfectly because in their eyes and for what they "tested" and for what it's worth, it _seems_ to run...