virtualbox.org

I get up my system ready then i see this message "fATAL no bootable medium found! system halted"., I was wondering if anyone could help me figure out how to fix it...

VirtualBox does not come with any operating systems, you have to install them. You sound like a fairly new user to VirtualBox. Since you are expected to know some basic terms before we engage in a meaningful discussion, I would suggest to start by reading three small chapters from the User Manual:

• 1.2. Some terminology,
• 1.7. Creating your first virtual machine and
• 1.8. Running your virtual machine.