I had logged off but, as I was shutting down for the evening, I thought of some additional tests you could do (based on the "Term::ANSIColor - Supported Colors" I linked in my last post).

If these work, your terminal supports 256 colours:

$ perl -E 'use Term::ANSIColor; use Data::Dump; my $x = colored("black
+ on white", "rgb000 on_white"); say $x; dd $x'
black on white
"\e[38;5;16;47mblack on white\e[0m"

$ perl -E 'say "\e[38;5;16;47mblack on white\e[0m"'
black on white
[download]

If not, these should still work (indicating you have 8 or 16 colour support):

$ perl -E 'use Term::ANSIColor; use Data::Dump; my $x = colored("black
+ on white", "black on_white"); say $x; dd $x'
black on white
"\e[30;47mblack on white\e[0m"

$ perl -E 'say "\e[30;47mblack on white\e[0m"'
black on white
[download]

For me, all of those give black text on a white background.

If you're down to determining whether you have 8 or 16 colour support, try these.

$ perl -E 'use Term::ANSIColor; say colored("red text", "red on_white"
+)'
red text

$ perl -E 'use Term::ANSIColor; say colored("red text", "bright_red on
+_white")'
red text
[download]

If the second of those looks brighter, you have 16 colour support. If they look the same, it's 8 colour support.

You might consider putting some, or all, of those in a script. That might help when trying various TERM settings (although, be aware that, without the ability to test on MSWin, I am somewhat guessing).