Ok... I'm running Windows 7 here, and I've managed to install and launch the simulator.
Did you get any specific error messages, during the installation or after when trying to run the program itself?
One possible workaround would be to right click on the start menu shortcut and "Run as Administrator".
If that works, you may want to try reinstalling outside of the C:\Program Files\ folder, as the permissions (what programs can and cannot in a given folder, or on a given file) are much tighter in Vista and Windows 7 than they were in XP.
As for compatibility mode, it involves right-clicking the shortcut, but this time, choose "Properties" and go to the "Compatibility" tab. Then, check "Run this program in compatibility mode for:" and choose either Windows XP, or 2000, or 98 in the drop-down list.
As for the virtual machine option, I'd say its beyond your level for now. Dual booting probably is as well.
I named Virtual PC, but there are others such as VMWare. It involves running a computer inside a computer, where in this case you'd boot a Windows XP system, running inside your virtual machine, which is a program running on your host OS, Vista.
When in a dual boot configuration; your computer has, "multiple personalities" so to speak: your hard drive is partitioned in at least two. One running Vista, the other running XP, with a prompt asking to choose which one you want to start upon powering your computer up.
Oh, one last thing. The messages we write here are "posts", not "e-mails". You may also encounter "PM"s or "private messages" which are accessible only upon logging to the forums and destined to particular individuals.
Have a nice day,