the computer in question is a MacPro5,1. For the last few months I have been using linux mint exclusively with no problems. Today I wanted to try another distro, and when i tried to start from a live cd, it starts to load, then immediately drops into a cli fallback mode. the output it something to the effect of : Busybox initramfs. then the machine just idles and nothing happens. I repeated the test with several different livecds (and different distros). all to the same effect. I have booted this machine from LiveCD's before (which is how i originally installed mint). interestingly i can boot from an external USB with OSX installed. Then I reset the NVRAM, and now the system does not even see the mint install that i have been using. Im starting to think that there might be some bad ram in the comp. but wanted to see if anyone had any advice or ideas. Im running out of things to try. any help would be appreciated (i need this machine to finish a few programming assignments). thank you.