Garmin trainer on Windows 7 works fine for me
The Garmin 400-500W series trainer works absolutely fine for me on Windows 7 Professional 64 bit Service Pack 1. Doesn't need XP mode - if you look at the system requirements its says it runs on XP on later. Once installed you can select the 430 simulation.
If you look at the (old) 430 simulator system requirements it specifically states it will not run on Windows 7.
RTFM - as they say.