i dont even know where to start.
"I have an 8 year old Dell Latitude"
could it be that maybe it's time to change this.
first off, i'm not sure you would be able to buy a mouse using serial, and if you can, it probably will be some 1980s vintage item that will cost you far more than you imagine.
As it is a mouse, you shouldn't need to do any wizardry to make it work, but it's almost guaranteed to be a ball mouse, and i'm pretty sure there are laws against using ball mice.
if your laptop is your only option because that's where all your illegal porn is and you cannot replace it or repair it, then .. well, it should be just a case of plug and play. still, i would seriously consider buying a new laptop.