After talking to Simian and now finding this thread… I think you should be able to boot.
Couple of questions, (I dont know that card) does it have a single power plug on the card – and if so are you using an adapter to get the extra plug or does the PSU have a dedicated line?
Also… what is nothing… does you computer POST – do you normally get a beep as it starts? Is it doing that but with no graphics? Same for the HDD led, does that flicker and go through a startup process?
Some cards I have met, if you unplug the extra power supply to the card will run in a low performance mode – try that & see if it starts.
Also, when its doing “Nothing” – press caps lock & let us know if the caps lock light comes on/off.