Sounds like they set a password - call Dell.

There should be a little box on the bottom right corner toolbar. The box should say Touchpad or something like that.. It looks like a little mini screen. Double click it and it should bring up all the pointer options and one of those is to disable the touchpad. (if its disabled then the icon picture should be a box with a red X through it)

the keyboard connector ribbon under the keyboard was proly popped out... Look in the online manuals to find out how to take out your keyboard , and re-set the ribbon. after that it should work fine again.