I first believed you removed the graphic card "and now the linux works"

From mandriva.com you can download the iso images of every of their distributions, I believe. It may take a bit of time to search them, for Mandriva will many a time suggest that you buy the commercial versions instead.

Since your Mandrake is dated from the windowsME era, I suspect you'll have a 9.x version.
If you've got enough power in the CPU and enough RAM (at least 1 Ghz and 500 MB of RAM, I feel), how about switching to the latest Mandriva, the version 2006 ? This one will be much easier to find on mandriva's homepage, and will be most likely to recognize allright your hardware ! And it will be prettier, Mandriva made progress in both stability and graphics, so did KDE and Gnome ^^
On the other hand, weirdly, I don't know of the ways you can find precisely which version of Mandrake you have already installed...