Dell vastro 1400 and compac

Hello,

am samuel, my two laptops are making worried.
1. i have dell vastro 1400 that works fairly because it shuts down more often after heating and the fun fails to work. a a friend tried to replace the fan then retruned the same, i restored factory setting in the syem and still make no change. what can i do?
2. compac has over stayed on power/everyday usage 24 hous for two weeks, later on it showed orange light on network wifi switch then diminished. i tried to lrestart, it fails till now what to do?