I successfully installed a dual boot with Windows ME and Mandriva Free 2007 on an old Evesham machine and it was working fine. Now I have added a KVM switch between this machine and my newer Gateway (Windows XP Media Edition)and it is working OK on the Gateway. But on the Evesham the keyboard cursor keys are not working on the boot selection and I am continually booting up in Mandriva. I cannot see how to get into the Windows boot. Once Mandriva has booted up, the keyboard is working fine. Any advice would be very welcome.
I am a complete Linux newbie and an elderly, totally non-techie lady, so please keep it simple in words of one syllable. Thank You.

are you using a usb keyboard?

Yes, I was using a USB keyboard, but have put on a PS2 one and it works fine. Many thanks for solution.

The BIOS on the computer giving the trouble may not support USB keyboards.

Sorry greengrocer, but if Mandriva works OK on the Evesham machine with the USB keyboard then I can't see the problem lying with the system BIOS. frndrfoe seems to have hit on an answer but doesn't explain his reasoning. That's a pity!

sometimes not all problems have a logical solution..something similar to this still happens to me too with a logitech keyboard and mouse wireless kit..every time the rechargable 1,5 volts batteries are going too down,the keyboard very often doesn't work well during boot but works again well in the os..and this both in Win and Linux..

i found the solution is changing batteries at this moment and voila ! everything works perfectly again !

I've seen it many times, particularly on older hardware, where the BIOS does not support USB. That means no USB keyboard will work prior to the O/S loading a driver, and also that usually means you cannot boot of a USB device.

You can have a situation where the USB keyboard does not work until Mandriva (or Windows or whatever O/S you prefer to use), has loaded a USB driver so that the USB root hub and the USB ports miraculously come to life.

At the point where you have the boot menu (where you select which O/S to boot), Mandriva has not yet booted (not even close). Your boot menu would be either Grub or Lilo yes? and at that point, the only bits of your computer that are working are the bits supported by BIOS.

@greengrocer:

Point taken

Some old motherboards support USB keyboards only if you turn that feature on in the BIOS settings. This means that no driver needed to use a USB keyboard and it will work with any OS (MS-DOS too) without any drivers. Just like a PS2 keyboard. If you don't have this feature in BIOS, than the keyboard won't be usable until an OS loads the USB driver.

In your BOIS look for USB KB Legacy Support, if it has that then usb mouse and keyboard are supported.