Cubase 6 - Mac - No Input Signal, Clipping and White Noise

Hi everyone, new here.

Just a quick bit of background:
Quite a few years ago I bought an Alesis io2 express which came with a copy of Cubase LE 5. I Installed it and that worked perfectly for a good year or so. Then one day I opened it and the problems began. Whenever I would open a project, my monitors just play constant white noise/static and feedback. If i press play to hear back a recording, i got nothing but the same constant white noise. The signal input bar would be completely clipping even if I didn’t have any mics or guitars plugged in. Long story short, it drove my crazy so I stopped recording and didn’t bother again.

So up to now, I decided I want to get back into it. I uninstalled LE 5 and got a copy of Cubase 6. Install went well (I’m running yosemite on my iMac) and once I open up the software I got the exact same thing. I have spent hours searching on the net to find a solution but I can’t come up with anything. The software runs well as far as I can tell.

Has anyone had anything like this happen to them? Its really been stressing me out lately sitting at the computer for hours each night trying to work it out.

So just to recap:
I can use the interface and my KRK’s to listen to iTunes, video games and web browsing but soon as i set Cubase to use the interface I get nothing, no sound, no input. If i go into VST connections and select the interface for the input and outputs. The signal input clips and stays constantly clipping, my monitors play back horrible white noise.

Would really appreciate any help I can get.
I can provide screen shots if anyone thinks they can help me.