OpenSuse installation disabled ethernet device on other OSs

I installed OpenSUSE yesterday on a system I already had Mandriva and WinXP. Ethernet worked fine on both of these. I had to **** around a lot because Suse didn’t recognise I had mandriva installed so I told it to install grub on /boot folder only and not set partition active but it made MBR point to its own grub so I was a while before I managed to find out how to get back to my old GRUB so I could boot mandriva and windows properly. Anyway, the thing is now the ethernet doesn’t work at all in both mandriva and windows. It still recognises the device but it says not connected even though it IS. funny thing is, network works in suse.
I installed OpenSuse 11, kernel version is Linux i686, KDE4.04. (I know KDE4 is unstable but I thought I could update to stable 4.1 right away).
I don’t see why installing a new OS would disable devices in another one, especially if that device works fine ine the new OS. If anyone has a clue it would greatly help. For now I’ll keep searching over the internet for suggestions on what to try.

A few models of NIC retain state as long as they are powered up and may be seen by other OSes as already active and so cannot be configured. Try disconnecting the computer from the power supply and waiting a few seconds for the power supply capacitors to discharge.