Alienware Steam Machine - Flashing Yellow Light on Boot

Hello,

I am having a problem with my machine and was hoping someone could help me. Similar to some other users I've seen, my Steam Machine is acting up and periodically refuses to boot - instead, the power button flashes yellow, five flashes in a row then a pause. I tried some solutions from other threads but nothing helped! If I leave it for a while, often it will decide it now wants to boot - but that's not acceptable when I want to play right now, not in two hours. Is there any help anyone can give to fix this problem?
Thanks in advance.