OK, so, I tried installing PHP (since everyone is so fond of it). This is for those who might want to repeat this feat.
Honestly, I suspect that all of my troubles come from the fact that I tried to deploy into C:\Program Files\PHP rather than C:\PHP.
So failed installation attempts:
ISAPI into C:\Program Files\PHP + Getting a driver for SQL Server from Microsoft here. Ended up with:
IIS 7.0 Detailed Error – 500.0 – Internal Server Error"
Then tried installing FastCGI by hand (also into Program Files). Ended up with:
HTTP Error 502.2 – Bad Gateway PHP
Then, downloaded the installation and installed as:
FastCGI into C:\PHP + driver was already installed
So my guess is it was all because of C:\PHP. Actually, I would try to verify that right now, but, with MSFT, it seems that if it works, don’t touch it ;) i feel stoopit.