any type of programs wont open

I have a dimension, only have had it a week. Three times now I have come back to the computer "woke" ( was not in hibernation, just screen saver) it up, after this has been done I can not open any programs, explorer, outlook, word, etc. Everything I click on nothing will  happen. When I go to restart a few windows pops up to say wait while this or that type of program is shutting down. After restart everything is working again with no problems. Just a few minutes ago we came home I went to check email. Clicked it opened, clicked to send/recve nothing happened it locked up. We were doing nothing at the time or before these problems, not dwnlding, installing, running mutible programs, nothing.......I'm at a loss with this. Like I said we have had this comp only a week. We purchased Dell because we heard such great things about it. Now I'm having more trouble in one week then I did with my old HP.