TRANSFERING VIDEO FROM DESK TOP TO LAP TOP

what type of HD is in there - IDE I assume? Get a cheap external IDE-USB adapter & plug it in to the USB port of your HP. Otherwise, you do need a screen & google win 98 to win 7 file sharing.

Or, just get one of these, remove the HD from your emachines and plug one end of the cable into it, the other into your laptop's USB, and transfer the files.
Windows 7 will play the videos without any problems, however I always suggest the installation of VLC media player because it is the best freeware there is and it will play practically anything.