And if I choose "Register" and enter my key, it says the key does not correspond to v21. This hasn't otherwise affected v21. If (not that it was necessary) I enter the same key in v21's OPTION\Register dialog, I get a successful registration.
I have only one v21 installation; it has both TCC and TCMD.
V ... Preferences/options ... Editor/CMD ... Use the following command processor instead of CMD ... if I give g:\tc21\tcc.exe (option "/q") and use the tool, I get the expired dialog. I can't rely on COMSPEC not changing to CMD because TCC itself changes COMSPEC to CMD whenever it gets WM_SETTINGSCHANGE, "Environment".
I must apologize again. It was my mistake, in fact, two mistakes. 1. I forgot that I had TCC 188.8.131.52 installed, and 2. when navigating in V to find TCC.EXE, I clicked on the TCC21 folder instead of the TC21 folder