Have a peek at precisely which version of IE8 is in use on each platform. You may find they are different versions.
Also, check the settings. IIRC, IE8 had a "compatibility mode" setting in it for compatibility with IE7, it may be set differently on the browsers. (This mode can be controlled by the web developer with a meta tag: http://msdn.microsoft.com/en-us/library/cc288325(VS.85).aspx )
For those who dont know, media queries are a CSS3 feature that rocks!
it effectively allows conditional CSS styling, how cool?!
but I was wondering does anyone have any knowledge of why they dont seem to work in MSIE 8 on Vista? MSIE 8 on XP works fine, windows 7 I don't know about though.
Anyhelp would be appreciated :)