Many older PC games are considered "abandonware"—games whose original developers are defunct, and copyright enforcement is inactive. While technically still illegal to distribute, downloading abandonware from directories is generally viewed as an act of digital preservation.
You can manually create an index by making a text file or spreadsheet listing all your games, their installation directories, and any relevant notes. Alternatively, there are software tools and scripts that can automatically catalog your games. parent directory index of pc games
Always use a reputable antivirus/anti-malware program to scan any file before opening it. Alternatives to Open Directories their installation directories
intitle:index.of "iso" "Half-Life"