IE auto-text in edit boxes...

I no longer use IE at home, so I thought I'd clear all its cached cookes, pages and so on. I found something strange though - I was checking if IE was allowed access to the internet over my firewall and went to AltaVista. To my suprise, as I started typing into the edit box, it suggested things I must have previously searched for long ago.
Interested, I checked that the purge had been successful - it had. I checked for the strings that were being suggested in the registry - but they weren't to be found.
So where is IE( 6, SP1) storing this information? I don't have any toolbars or plugins installed so it must be standard behaviour... and on a side note can the "show previous text" option be disabled - in the advanced settings the only related option was about inline auto-complete, and that was turned off.

Thanks for anyone who can help me clear up this mystery.

Did you clear history? Also, you can set save history to 0 days, which cuts down on the clutter. And clear Run... history.

Done all those things. Which is what makes it peculiar. Like I say it's not in the registry, I could start a full file-search but has anyone got a idea where to look?