Did I buy the correct RAM? (pre 09 macbook)

Did I buy the correct RAM? (for pre 09 Macbook)

I have a pre 2009 13in white macbook intel core 2 duo 2.1 ghz processor, model identifier 4,1.

I did a ton of research (although evidently not enough perhaps) before I made a purchase on a RAM upgrade. I currently have ~2.5 gb of ram, and I wanted to remove my 512mb card and replace it with a 2gb for a total of 4gb.

Tha 2gb card I bought is this one (different seller):
Hynix 2GB DDR2 Memory So DIMM 200pin PC2 5300S 667MHz HYMP125S64CP8 Y5 4260193742019 | eBay

I installed it and my macbook booted up with the dreaded 3 beeps. I looked on Crucial's website and it looks like this would be the correct RAM to order if I bought it from them:
CT25664AC667 - 2GB, 200-pin SODIMM , DDR2 PC2-5300 from Crucial.com

Also eshop:
Apple MacBook Memory DDR2 667MHz up to 6.0GB and up to 750GB Internal Hard Drive upgrades too

I don't understand the difference between these besides the brand. Knowing my luck I probably overlooked something completely obvious, or got a DOA product.

Any help is appreciated, thanks!

The Hynix is the correct memory.

But, Macs can be picky about RAM.

Hence, we don't recommend buying the cheapest stuff you can find unless you know it's going to work with a Mac.

You can try it in a different slot and by itself.
Make sure it's inserted all the way.
Could be the stick is bad, could be it's not going to work in a Mac.
Either way, return it and get your memory from OWC or Crucial if you're not familiar with the various manufacturers and the differences between the different grades of memory within a manufacturers line.

And personally, I'd suggest, don't buy any more RAM from ebay.

I'd be looking at the 2GB stick you already have in the machine and getting another from the same manufacturer.