The Rules:

xBill has been painstakingly designed and researched in order to make it as easy to use for the whole family as it is for little Sally. Years - nay - days of beta testing and  consulting with the cheapest of human interface designers have resulted in a game that is easy to use, yet nothing at all like a Macintosh.

I.  Whack the Bills (click)
II.  Pick up stolen OSes & return(drag)
them to their respective computers
III.  Drag the bucket to extinguish sparks
IV.  Scoring is based on total uptime,
with bonuses for killing Bills.

As for the rest, you can probably figure it out.  We did, so it can't be too hard.