How many geeks does it take to fix a server?

I'm stumped. My web-server (Microsoft's IIS 6.0) is corrupting pretty much every binary file it transmits. I first noticed this when AVI's from iiproductions.org would have static introduced or wouldn't play at all. Then I realized all ZIP files from any of my sites weren't working too.

The real kicker is that my network of fellow computer geek friends are stumped as well. This is huge, as 2 of these guys are network techs and they live and breath this stuff... with pimped out networks at home. They don't just punch out of work for the day and try to forget what they do; they love it! And they are baffled.

This entry is happening to vent, and potentially have that one person come along who knows what the problem is and comment / e-mail me. After various searches through Google and Microsoft's KB articles, I don't know what else to do except either

1. Format the system and re-install Win2003 and IIS
2. Install Linux (or keep with Win2003) and Apache