USR Folder Deleted

The USR folder was deleted off my mac mini without understanding the implications but was backed up onto an external HD beforehand. The mac instantly shut down and now when turned on straight away reads the kernel panic 'You need to restart your computer'.

I have tried connecting the mac mini to a mac book pro in target disk mode to replace the USR folder but the mac is unresponsive to ANY startup key sequences. I have also tried running the original mac os x install discs but nothing happens, and the only operation I have managed it to complete is ejecting the cd using mouse down.

If anyone has any ideas about how to get my mac working again it would be much appreciated.

/facepalm

This is why your home folder has default places for you to put all of your stuff and why if you don't know what a folder is and it is outside of your home folder (aka before it in the file path) don't delete it.

I'll keep thinking and maybe come up with something.

I don't know why your mac isn't booting from the install disc. Until someone fixes that issue, I've got nothing.

You might be able to get some access in single user mode. "command + s". f so, you may be able to mount an external volume and restore from it. Lots of folks seem to be posting about having deleted /var, /usr, /etc and the like lately - not sure why.

You have lost a good portion of your operating system by deleting /usr. That is why your system will not come up. Which install disk did you try to boot from? Make sure the disk you are using is bootable.

rman = Oracle guy?