I have encountered such a problem several times.
When I was using Microsoft Netmeeting, the
computer crashes. When I restarted the computer,
my C(opengl) program (using Tcl/tk) cannot run
any more, even after I reinstalled ActiveTcl.
In my program, I used TCL/TK+TOGL. If I only use
Tcl/Tk, it itself seems to be OK. It
shows 'Application Error' Dialog box when
I run my program. I am using Windows 2000.
My solution to this problem is reinstlling Windows.
This time I hope I don't do it again. :((