Could not find Sikuli window after a failed test

Hi,

I am running 64-bit Sikuli on 64-bit Windows 7, with the latest updates.

I started a test, and the Sikuli window disappeared and never came back, even after I killed the target of testing. I restarted my Windows, and started Sikuli again, as:
  C:\Program Files\Sikuli X>Sikuli-IDE.bat
  [info] locale: en_US
or as clicking on "Sikuli-IDE.exe" directly. The Sikuli window does not show up.

I have removed the Sikuli script and its folder, and restarted Sikuli. The Sikuli window does not show up.

I have also re-installed Sikuli. The Sikuli window does not show up.

Last time I asked our system admin to go into my registry and kill every reference to Sikuli, and then reinstall Sikuli to get rid of the problem. Since Sikuli is a java program, getting its status from preference, I guess that I need to kill the java preference to resolve this issue.

I checked the Sikuli installation folder and did not find any error logs.

I checked the Task Manager, and could not find any name obviously related to Sikuli.

Any idea on on how to resolve this issue?

Thanks, and
Regards,
CP