A quick note in this thread that might help out somebody else experiencing issues with VT not wanting to launch (specifically on Windows 7).
I've been out of the country for a bit, and my computer rebooted while I was away, and thus VT wasn't running. When I tried to launch it upon returning home, no deal. Spinning mouse pointer for a bit, and then nothing. I _THINK_ that it was a Java update that might have caused the change. By that time there was ANOTHER Java update available, so I installed that hoping to resolve the issue, but no dice. Updating VT to the latest version also did not fix the problem.
Doing some trouble shooting, the JRE process was spawning, and then terminating within a couple of seconds. I launched VT with verbose Java error reporting enabled, and got a series of errors related to parsing some manifests.
I tried clearing the Java app cache, and that didn't do it. I ended up doing an uninstall of all cached applications, and that fixed. Note that this doesn't uninstall VT, it just forces Java to reload everything app related afresh. That did the trick.
For windows, you do this by navigating to your JRE program directory, and executing:
That will spin for a bit and then return to the prompt. Subsequently launching VT will take a little longer as it reloads the local cache, but it then worked fine for me.
Hope this helps...