Mom and Pop stores on Long Island... Hrmmmm... No?
There's at least one more CompUSA, or was, anyway. If you take Northern State Pkwy all the way eastbound until it ends, it terminates into... either 25 or 25A, if I remember correctly. Continue eastbound, and there'll be a CompUSA on the right (if you hit Smithhaven Mall, you've gone too far -- or it's closed.) My first girlfriend lived out there, so I was out there fairly frequently.
It might be a good idea to check MicroCenter -- they often have returned goods at a discount... and I've bought a couple items open box and have had NO problems with them.
I don't think there are really any Mom and Pop stores around... there's one place just north of the intersection of Jericho Turnpike and 110 in Huntington -- again, there "was" one -- that's from two years ago, when I worked in the building next door to it -- I always saw the signs, never went in, though.
Most of the small shops around here can't stay in business, I'm gathering... they must not be able to make enough money. The few places I have seen are all definitely suspicious. (Have you ever gone into Labelle? It's amusing as hell!)
I know it's often more convenient to have a local shop, but in this case... you're pretty much screwed. CompUSA is around, Best Buy, Circuit City... that's about it. Really can't think of anything beyond those... rather unfortunate, really.
Of course, where I am in Boston when I'm at school, I have a CompUSA I can PAY to take a cab too (*bleh*), a MicroCenter I can almost walk to (not in this weather), a Best Buy at the end of an hour long subway ride, and a University Computer store that overcharges so outrageously I'm surprised they stay afloat... and I also have a T1 conection to make all my purchases over.
Here though... *shakes head* There's not much.
Andrew
PS: I'm in Plainview, but went to High School in Mineola (Chaminade), and my mother grew up in Oyster Bay, so I've been up to that area every once in a while.