If you do not press any key to continue, the CD/DVD boot process will time out and proceed to the next device configured for boot - which in your case is an attempt to boot from the network via PXE boot. You get this same message when you install copy of Windows on a physical machine from USB or DVD media. To do that with a VM you have to click the mouse pointer within the VM's window and then press any keyboard key But It's also telling you that you have to hit any key to continue the boot from the CD/DVD drive - continuing the boot from the CD/DVD drive is what starts Windows Setup. It means you've successfully completed the initial boot from the ISO. The message you see 'press any key to boot from CD/DVD' is a message from the ISO install media you've configured in the virtual CD/DVD drive. From what you're saying, I suspect that you are not performing the steps necessary to complete the CD/DVD boot.
