Domain indexed as example.com/?tag about 4 times

Google thinks they're separate pages...all dupes of course.

[walkman]

My domain has been indexed as example.com?tag about four times...with different tags of course . When I search for a sentence I get my www.domain.com displayed and this:

"In order to show you the most relevant results, we have omitted some entries very similar to the 1 already displayed...."
if I click, I get another listings, all identical (cache a bit older).

Apparently Google things that these are pages and since they're identical I might be penalized. My traffic has been reduced to almost zero since August and this is the only thing I can think off after going through 4 months of nightmare looking for and fixing things.

These .com/?links are left over from last year when I linked to track things. The links have been long removed but still show as supplemental and apparently Google doesn't want to drop them. I never had any problems but maybe in august Google tweaked to include these. Who knows and this is costing me money....

How do I get rid of them?
Can I use robots.txt, rewrite, redirect, anything?
How do I tell google to stop indexing them...give a 404, redirect or whatever... If I can block G from indexing I would link them again so the cache would be replaced with another simple page or ideally give an error so the pages and links are removed.

Whatever it's needed...I have no choice.

I woudl appreaciet any help,

[edited by: ciml at 12:23 pm (utc) on Nov. 29, 2004]
[edit reason] Examplified [/edit]