Ok, so being a windoze slave for many years now, I have used Roboform. It is a password and form filler management program. No Linux version :(

Any ideas for a good reliable secure replacement for my Mandriva?

I don't use a program like that, but I believe that Sxipper is close to what you're looking for: Sxipper

Alternatively, you could use Roboform with wine: Roboform with Linux

Welcome aboard!

Or maybe Kdepasswd​ if you are using the kde desktop.