You know, if it were a site other than Hotmail, I'd add it to the Restricted Sites Zone, so that it is prevented from auto-doing a thing. But since it is Hotmail, its functionality depends on it being allowed to run some scripting. The problem still must have something to do with the scripting command it is doing for those files. Next time you're there, it could be informative to do a View Source and see what command it is invoking for your click on those file links. It may even turn out that you can find some one to turn off part of Hotmail's level of permission and still have the rest of the site work. Configure a special Security Zone for it... But it'd take a lot of probing and time, trying to work it out that way. And myself, not a Hotmail user, cannot offer any bits of info about what kinds of scripts Hotmail likes to run.
About the autoplay of multimedia in general, there is another MSIE setting to consider. Accessed from the MSIE
menu bar -
_Tools > Internet _Options > "Advanced" Tab.
Multimedia:
[x]play animations [x]play sounds [x]play videos
You could in theory put a pair of .reg files on your favorites or links menus to toggle on and off those multimedia autoplay settings. On my w98 system, the reg files that work are below. On an NT+ system, the first line I think is REGEDIT 5, and the registry key itself, be best to confirm that it's at the same location.
--------------MULTIMEDIA-AUTOPLAY-ON.REG-----------------
REGEDIT4
[HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main]
"Play_Animations"="yes"
"Play_Background_Sounds"="yes"
"Display Inline Videos"="yes"
--------------------------------------------------------
-----------MULTIMEDIA-AUTOPLAY-OFF.REG------------------
REGEDIT4
[HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main]
"Play_Animations"="no"
"Play_Background_Sounds"="no"
"Display Inline Videos"="no"
--------------------------------------------------------
I think that approach would work. Although it is not the most desirable. Having to remember to click the .reg files on and off each time you're at Hotmail. This multimedia settings here unfortunately are global; I can't see that it is one of the things where you can assign sites to specific security zones.
Another possible approach? A different browser, specifically for visiting Hotmail. Opera maybe. Or one that you should experiment with for this: OffbyOne.com. The OB1 browser has multimedia toggles directly on the menu bar.
I use OB1 myself anytime I visit msdn.microsoft.com, since it is the only browser on my machine that makes that site functional and easy to read.
So those are the workarounds that I can think of. As to the heart and truth of the matter, it sounds at this time like it has something to do with the kind of scripting Hotmail is using...something you might examine with a view source on those *.asf links.
But what to do about it, once you have some of that info, well I don't know. I'm thinking of all the time I've spent battling the site I was mentioning -- msdn.microsoft.com --with its not rendering things in a civilized matter....and I cannot say that I even gained any real knowledge. Only a workaround (using a non-MSFT browser for that MSFT website).
Best,