virtualbox.org

I have a MacBook with Max OS X 10.6.8. I would like to run a version of either WIndows or Linux, so that I can use a program called Holotable which is not available on Mac.

I have downloaded Virtual Box, and then when I attempt to run anything, it tells me "FATAL: No bootable medium found! System halted." The User Manual was not too helpful.

What is the easiest way to get Windows or Linux up and running on my Mac VirtualBox?

What do you expect? VBOX emulates a PC. But is has no guest OS preinstalled.

So you must have a guest install medium and then you have to install the guest os like on real hardware.

For further details look into the faq and the manual.

You would have to buy a Windows OS license (with CD with setup key) if you want to install Windows - or perhaps you have a Windows setup CD lying around.

Linux setup ISOs are freely available for downloading from the net. ISO is very convenient as you can mount them in the virtual machine directly, boot, and run the install.