I'll preface by saying the 'questions that may already have your answer' haven't helped me.
Ok, about a month ago I installed Ubuntu onto my Mac Mini, it worked. Then the Mac Mini went under my bed and sat there doing nothing for a month. I dug it out and put it in my flat's kitchen hooked up to the TV today and it appears to be dead.
When I turn it on, after the initial white Mac startup screen, the screen goes black, then a black screen with a white flashing dash appears. After that the screen goes to the purple 'Ubuntu 12.04' screen with 4 dots that each light up. After this, there is a lot of white (and some yellow) text, then the text stops scrolling and just stays for hours. When I begin holding the power button to turn the Mac off the text starts moving again until the computer is off.
It's driving me mad and I want it working before some flatmates get back tomorrow so I can continue watching movies in there.
Just to add, I no longer have an OSX partition. It's all Ubuntu, I do have a separate computer running Windows 8 which I can use for creating bootable USBs and such.