Do what I tend to do in those situations: Just buy a new HD and put into the machine. No baggage to be careful with, if the installation goes bad you can wipe the drive clean and give it another go. If you're happy and need stuff from the old HD, just put it in an enclosure and plug it in as an external USB drive.
Plus, if you decide you didn't like Linux at all, just put back your old rusty HD and chug along with Win7.
In a Full Windows Environment I use MS SQLServer Express, however If there is mixed one (web and CS) I preffers MariaDB (you get tons of samples in php code). In Addition to it our programmers are very conforable with both.