MacBook Pro keeps resetting when away

Howdy,

I have a 3 year old MacBook Pro running the latest OS X OS. Before a few weeks ago, if I went away from my laptop for more than 10 minutes, the system would go to sleep. When I came back the LogIn screen would show and after entering my password my home screen would come on like always. If I had open programs they would still be in the same position as they were when I left.

Since about a month ago something has happened. Now when I come back the Login screen is there but after about 2 minutes the Home screen comes on but it starts as if the system was turned off after I left. Any program I left on is no longer on. It appears I loaded a program or modified an older program to do something different when the system is left alone for 10 minutes.

I'm not looking for someone to tell me all the programs to look at but instead, is there a quick way of finding a program on my system that may have changed or is currently set to do this? This really sucks having to come back to a shut down laptop every time.

Oh, one more clue I just realized is different. Every time I come back and the laptop opens, the Trash has stuff in it. It appears a program sweeps my system and when it's finished turns it off. Any ideas?

Thank you!