Just got a 2008 macbook and i can't install osx it comes up with temp unavailable

You need to install an earlier OS from a disk, and then download the one you’d like from the Mac App Store with your own Apple ID.

(142440)

You need Snow Leopard 10.6.8 to upgrade.

Visit an Apple Store, call 1-800-MY-APPLE, .

This is what the seller should have done, which will give you some general guidance.

Selling old Mac (4) Apple support