Since there are only a few pages that actually use ASP code (form scripts) you can re-write them in PHP.
If you need to retain the .asp extensions due to the pages already being indexed by the Search Engines, you can use .htaccess to tell the web server to parse .asp extensions for PHP.
Installing, configuring, securing, and maintaining your own web server for the first time is not something you do for a live web site - you experiment with it for a few years until you know what you're doing.
Making a sacrifice of features by running in Windows Safe mode doesn't make sense with all the cheap web hosting that's out there.
If I had to choose between moving the site to a Linux box (and re-writing a few forms scripts) or learning to do database work in ASP... I think the Linux box is easier.