In XP if we opened a gif pic in the default program it worked fine, but in W7 it does not animate.
I am thinking about getting W8 and would like to know if gif works in it.
If I remember correctly xp used internet explorer by default to open images other then bmp.
Your problem isn't that that windows 7 don't support animated gifs but that it no longer opens them via browser by default.
You only need to set the default program to something that will support them such as ie, firefox, chrome or an animated gif editor.
If you're going to install a third party viewer, might as well install something like Irfanview - http://www.irfanview.com/ - which is both free and massively capable in as much as it'll display pretty much any image format known.