Hardrive for Dell Inspiron 8600

I'm looking for an aftermarket replacement hard drive for a dell inspiron 8600. We ordered this: http://www.newegg.com/product/product.asp?item=N82E16822144376 and it won't fit, even though newegg said it would. It has a form factor of 2.5", and it looked like the old dell hard drive had shorter pins. I can't find much specs anywhere so does someone know of one that would work? thanks a bunch.