He downloads the ISO himself to a modern PC, runs it in a highly accurate emulator, and watches the old blue setup screen scroll by one more time. He thinks of Dr. Thorne’s trembling hands. The impossible bridge. The 2:17 AM download from “TapeWorm,” whose real name he never learned.

It’s a machine. Not just any machine. An HP xw9300 workstation. It’s a beige beast with dual Opteron processors, four gigabytes of RAM—a king’s ransom in 2005—and a professional Quadro graphics card. Its owner, a frantic architect named Dr. Aris Thorne, paid Leo five hundred dollars to bring it back from the dead.

It allows for the execution of 64-bit applications while using the "WoW64" (Windows on Windows 64-bit) subsystem to run most 32-bit apps. Where to Find a Windows XP 64-Bit ISO