Power saving mode

Posted this in the normal dell desktop forums but then saw the sticky thread at the top telling me to come here for alienware issues. ill just copy and paste it;

I've got an Alienware Aurora, basically whenever I turn my PC off, when i boot it up the next morning it randomly goes into power saving mode within 10-15 minutes of it been turned on and theres no way to get it out of it except to do a forced restart holding the power button down on the tower. But say if i leave it on all night, it'll be fine, its only when it gets turned off and booted up again that it just seems to go into power saving mode by its self. I've even tried just putting it into sleep mode over night, but then when I brought it out of it, it went into power saving mode 5-10 minutes later.

Sometimes it goes into power saving mode before i've even got to the login screen (It's not that i've left it too long idle, I'm sat there waiting for it to boot up and it'll just go off) I've checked all the power mode settings and theres 100% nothing in there thats wrong. It's even been looked over by our technical support at work and they can't see anything wrong either but they're none the wiser to why it's happening. If the computer gets past the first half hour it won't do it, i can't remember it once happening in the afternoon, its just when it first boots up, wierd.

Its been suggested it could be the monitor, but i tried a spare monitor here at work and it still did it, so it's not the monitor. It's been going on for the best part of 2 months now, it's not covered by warranty anymore. 

Any ideas?