From what you describe it sounds like settings to me. It seems your monitor is just going into regular standby. Try going into advanced power settings as well. That gets more specific.
As far as the monitor turning off on you when you start your computer, i think that is normal it depends on the brand of monitor / operating system sometimes i believe. I have a gateway 22inch monitor and when i start my computer the monitor turns on like normal, but before it can load into windows it times out and turns back off, probably because right after windows boots, video memory becomes software controlled and thats what its looking for. But after a move of the mouse it turns back on. It did this with WinXP and it does it even longer with Win7.
Definately try taking a couple screenshots of all of your display settings. That would greatly help.