jjimm, sorry for the delay in getting back but I am traveling and my internet access is extremely limited these days and I cannot do the tests I could do in my own computer. Anyway, I looked at a computer running IE6 and you are right, the files are stored in subdirectories under windows/temporary internet files/content.ie5 (go figure). I assume it is the same in IE5. There certainly is an index file in that directory.
I am quite certain earlier versions of IE used a common cache files but now I would want to double check as I have been absolutely certain of things which were later proved wrong.
Anecdote:
A few weeks ago I wanted to buy something online but the order would not go through so I called the vendor and they told me I needed to make a small change to my credit card info so I went online to my credit card and made the change and then placed the order. . . . . . or so I thought.
A few weeks later I access my credit card account online trying to make the same change again but I cannot find the page so I call them on the phone and asked them where I could find that page. The guy told me it could not be done online but only by phone. Huh? I just did it a few weeks ago!
Me (not accusing him but sort of musing to myself): So, You are telling me I am making this up in my mind, huh?
Credit card guy (in an apologetic tone): Oh, I would never be so rude!
Me: No, no, I did not mean it that way, just that, in fact, I am mistaken?
him: yes.
So, here I was absolutely certain I had done it and yet that was impossible. Later I concluded my mind had mixed up two things and what I had actually completed online was the order for the gadget but not the credit card thing. Sometimes our minds play tricks on us.