"...there's ALWAYS a way..."

A while ago (2011?) I purchased a copy of "Dawn of Discovery Gold Edition" from GamersGate, one of the larger online game distributors.  I'd installed it, then later on found that I needed to free up some hard drive space.  I uninstalled it (though I can't remember if I'd used the "Control Panel" or from my start menu.  Anyhow, later on (about a month or two ago) I wanted to try reinstalled it onto an external hard drive.  Upon downloading the 4+ gigabyte file, the pretty intro launch screen started up, but when I clicked the install option, it was rejected, saying the program was still installed and would need to be removed first.  Well, the game files were no longer there, and being the stubborn type, I did the natural thing:  tried a couple more times hoping the computer gods would look upon me kindly for my sacrifice of bandwidth.  Result:  same.  Even sent an e-mail to GamersGate, to which they responded by saying that the game essentially couldn't (or, rather, shouldn't since it appears it doesn't recognize 'long' directory names) be installed on anything except the root directory - so, their 'solution' was to re-download the file and reinstall.  This still didn't solve the problem.  So, I pretty much knew I was on my own with this one - it was going to take some ol' regedit magic.  But, before proceeding, I'd noticed that there was a (relatively tough) protection scheme for the program:  Tages.  So, armed with that knowledge, I started the (always potentially hazardous) registry editing.  Basically, I first searched manually in the 'software' keys for the game title, as well as the manufacturer.  After that, i figured I'd play it safe, and starting at the top of the registry file, I did a 'find' for the term 'dawn' (EVERY instance).  One by one I checked those particular keys.  If I knew for sure it wasn't related to the game, I skipped ahead.  Otherwise, I deleted it.  Crossing my fingers, I then re-downloaded the game file (again), and voila - it worked (though I still played it ultra-safe, by installed on my root drive instead of the external I'd hoped to put it on).  One more note:  I kind of screwed up, but got away with it, by NOT making a backup of my registry before editing it.  Otherwise, everything seems fine.