My computer is auto-filling forms on sites even tho I have taken all measures to delete history?

I use Mozilla Firefox to browse the web, and I always clear all private data, clear all IE options, do not save any forms, run CCleaner, shut down my pc, and disconnect my modem when I log off for the day.

Now I find that when I come back online, and open Mozilla, then go to bookmarks, and locate a bookmarked question I have participated in on Yahoo Answers, it auto fills my Yahoo ID and encrypted password for me to log in.

The only possible explanation I can think of is that the forms have been saved in the bookmark, but I can't see how. I thought only the address was bookmarked, not the private data.

To me, this was a serious security fright, when I thought I was being very vigilant.

Is the problem in the Mozilla bookmarks, or have I missed something?

I run many antispyware apps, and a reputable security suite, both of which are always up to date.

Any clues??

My computer is auto-filling forms on sites even tho I have taken all measures to delete history?vista

Open Mozilla click on tools on the very top of the page to the right , then click options in the drop down menu then click on security then un-check the box for remember passwords then click privacy then check the box that says always clear my private data when i close firefox . that should resolve your problem

My computer is auto-filling forms on sites even tho I have taken all measures to delete history?antispyware

IE - tools, options, content, auto complete.
If you are using IE just reset your browser by clicking tools internet options click advanced tab and at the bottom click reset. When asked for auto complete after resetting say no.