Firstly, I appreciate your reply... in fact, any help I can get.
Secondly, I have spent some 100 hours (in the past 10 days) rewriting and testing the last 20% of my code to change my website from ASP to PHP. It is now live and kicking... Woohoo :)
This means to me that any older issue is most likely not relevant any more. There was a 'canonical' issue that caused my page to drop off the Google index. This has turned around. I am back from only 78 links to 304 and climbing -- you should see my happy smile. :)
The conversion to PHP has some things handled differently.
I optimised and cleansed the code; now 10% leaner.
So the new site is virtually a new venture (same contents and behaviour though).
Some of my 404 behaviour / code is different.
While it still redirects pages "very_old_url" to "new_url", as in static URI "corrections", I have no handling of dynamic URIs (yet).
Hence, the new problem of show.asp?query=123 leading currently to a 404.
Since I am now on Apache, I can use rewrite rules.
My question was how do I get show.asp?blah=123 to be answered with contents rather than a 404.
I have figured it out with the above RewriteRule.
And here comes my ignorant part that probably annoys you: I did not look back what I posted before, because I got this new thing now :)
In case you referring to this post [webmasterworld.com
...] -- for me this was a different problem...
Another kettle of fish is the art of rewriting URIs, friendly URIs, proper redirects, proper HTTP codes and all...
I am a programmer by necessity, not by occupation, hence, it takes a lot of research and learning (and making mistakes) before I can tackle a specific problem. Once it has been solved I won't touch it unless it is broken or technology has moved on. Hence, I might be fully across a specific problem now, ask me in a year and I have forgotten it all...