|"I didnt have to install a patch with my old laptop?"|
Maybe you should have. There have been several patches made available since the original release of DOOM 3. Each one of them contains bug fixes & improvements. The patches *may* have been downloaded & installed automatically if you used the auto-updater, but if not & you've NEVER patched your game manually, you've probably missed out on a lot of improvements. Patches are a way of life in the gaming industry. That is true of almost ALL games. Did you bother to read what this particular patch is for??
"This is the newest release from id Software that improves Vista compatibility, the SDK as well as fixes several minor bugs in the game among other things"
You keep mentioning your old laptop. Did your old laptop have Vista or Windows 7? NO, it had XP...stop making comparisons! Do you realize that Windows 7 is Vista?? And as stated above, patch 1.3.1 "improves Vista compatibility". Why would you think there's a virus in a patch that was released by Id Software, the developer of DOOM 3?
Maybe this article will help: