You could install Mandrake, but I'd advise against it- it is no longer supported, there will be no security updates, and, well, things are mostly much better now.
You are welcome to try Mandriva, but I like kubuntu very much. I like KDE3. Best of all is the system used by the 'bubtus for software updates and installing new stuff. The "Debian way" of doing these things is good, better than mandrake's urpmi was.
I am running kubuntu 8.04 (LTS). LTS="Long Term Support", and it's good for another year I think.
8.04 comes with KDE 3.5 which is likely to be what you will be used to (Though it is better, faster, more functional and prettier than Mandrake's KDE3 was).
The "newer" Kubuntu (9.10) comes with KDE4, which I happen to hate.
If I install [kubuntu] instead will my old mandrake system work on it?
I don't understand the Q.
A modern distro comes with all (and more) software that Mandrake had, so you don't need Mandrake any more. A modern distro has support for just about everything USB, bluetooth, wireless, and right now I am playing with a USB GPS device, which worked out-of-the-box with ubuntu 9.04 (No, not K
ubuntu, I'd rather use Gnome than KDE4!) and tangoGPS.
Let us know how you get on. Good luck.