Help with a new computer please?

Tweet

I have a new little computer that I bought- it is an EMachines and it uses Windows Vista as its operating system. Here is my problem; Somehow it is set to shut down to the lowest power setting every time I have been away from the keyboard for about five minutes. Every single time I leave the room, it shuts down to this quasi-shut down setting and I have to restart my instant messenger, etc...I have a 17 month old daughter, so needless to say I am up and down a lot! So, can anyone possibly tell me how/where to change that setting so that it has to be idle for much longer before doing this? Thanks so much, it is really irritating.