Run setup.exe from the mounted virtual drive. Install to a folder like C:\Games\GTASA (avoid Program Files to prevent permission issues).
Do not just type "GTA San Andreas download." Use specific search strings on archive.org:
Key identifiers: Look for the HOODLUM or ViTALiTY release names. These scene groups cracked the original DVD.
Sometimes uploads labeled "new" are actually the 2014 mobile port back-ported to PC/PS2. Avoid these. They feature a different UI, broken lighting, and missing cheats like "Flying Cars."
Verdict for the purist: Look for a USA Version 1.03 ISO uploaded within the last 90 days.
There is also a new trend of uploading the PS2 Classics version (the official emulated version sold on PS3). These ISOs are slightly modified to run better on Sony's proprietary emulator, but they are also being preserved on Archive.org as "new" dumps.
It is important to clarify that you cannot simply double-click an ISO file to play the game on a modern Windows 10 or 11 PC. You need two things: