X displays but console doesn't: vga=?

[Michael West <quagly@mitzit.net>]

I cannot get to a console, but X works fine.  If my runlevel is set to
start graphically my monitor flashes "Invalid Scan Freq" three times and
then works fine.  If I start in single user mode it flashes "Invalid
Scan Freq" forever.  when I pass vga=ask to the kernel and select 80x25
the result is the same.  When I choose "scan" it never comes back.  

I have been using the same monitor and video card for 3 years, but this
just started last week when I put the card into a different box.  The
old motherboard is fried so there is no going back.

What is the next step in diagnosing?