You wouldn't happen to have a Logic XSkey plugged in, would you? Try removing it.
It's a known bug, and if I understood Peter correctly, something that is being adressed by SoFo in cooperation with Emagic. Knowing that Emagic's PC division went down the drain six months ago, it might take a while to get it worked out, though.
OK, apparently what happens (any SoFo guy correct me here) is that Vegas goes looking for HID's (joysticks etc) and when it finds the XSKey it starts querying for HID info, the XSkey goes "say what?" and Vegas bonks out.
Now.
The fact that you removed the dongle WOULD have solved the problem if it had been an USB one, since they're kinda plug-and-play. If it's parallel port dongle it might explain why Vegas still crashes. I *think* you should be able to check out the registry (search for Emagic, perhaps) or clear the drivers for it by selecting "remove device", "show hidden devices" and see if there's some sort of XSKey driver you can kill.
Make sure you have the Close Audio and MIDI ports preference turned on in Vegas. This forces Vegas to close the ports when it looses app focus (and it isn't playing.)
What ever app you are using that also uses ASIO, then make sure it can do the same thing.
ASIO is really a one app driver model. Some drivers behave nicely, others will crash and burn your system (BSOD) if you attempt any kind of sharing.