You can install MySQL on a Windows machine with ZERO interference to SQL Server, to ASP, or to IIS. I know. I have done it several times now.
And have then even used MySQL and SQL Server on the same system, using ASP connections to each of them (and, yes, even with a single ASP page connected to both at the same time for a couple of apps).
You do need at least a Remote Desktop connection to the server, though.
It's not hard. Just download the MySQL version you need and run the default installer. Take all the defaults (be sure to say "YES" when asked if you want it to add MySQL to your ENVIRONMENT variables). Done.
Never installed Wordpress, though, so can't help you there.
An optimist sees the glass as half full.
A pessimist sees the glass as half empty.
A realist drinks it no matter how much there is.