I have been thinking of an idea for a Slasher Game and was curious if anyone knew of a system for such setting?

World of Darkness in general.  More specifically, World of Darkness:  Slasher and World of Darkness:  Midnight Roads should both have stuff for that.

Is that New world or Classic?

New sort of, I think.  Those two titles are part of the line called Chronicles of Darkness I think.  But you should be able to google them under those titles.

Chronicles of Darkness is the new brand for New WoD, actually - as well as the name of the NWoD 2E rulebook. The two books you mentioned you were written for NWoD 1E.

Aside from that, I think you could run a slasher game in just about anything? NWoD, GURPS, Call of Cthulhu...

I know any system can run any type of game if you're creative enough but I was looking at things that already had mechanics built for the nearly one sided onslaught that slashers unleash upon the unsuspecting.

If I used MnM I'd set the slasher at pl 8 or 10 and the civilians at pl 2. Or if I used a level based system, like D20, I'd have the slasher at a level probably double that of the players.

Well, NWoD Slasher definitely has some special rules for slashers to make them deadlier than an ordinary person. Not sure if you'd like to purchase this book, though, as it's a big book with lots of material dedicated specifically to the NWoD setting (especially Hunter: the Vigil).

GURPS is, of course, an universal system. It's crunchy, but should work well in a gritty horror story. The GURPS Horror supplement has (among other useful things) a lot of write-ups for horror monsters, including slashers.