If I drop a new harddrive that is still in it's plastic case on the ground, is it ruined for sure?

Only one way to find out...

Hook it up and look in BIOS, listen to it for clicking sounds etc

The answer is a definite maybe. It could work fine and never have a problem, it could work fine and fail prematurely or it could fail to eork at all.

Do what FTT said and then you will at least know if you killed it....

By the way, how long was the drop and what did it drop on to? 10 foot drop on to a concrete floor is different from a 3 foot drop on to the den carpet.

...and if terminal velocity was attained... ;)

Well, I had it sitting on top of a bigger box (I was trying to be efficient by carrying the bigger box at the same time...silly me) and it slid towards me and kind of down my body about 3 feet on to the cement. It didn't come out of the plastic case, but the plastic case did pop open. Ay de mi! :eek:

When I went to build my Asus and Barton system, I dropped the CPU to the floor (wooden) about 3 feet, but it survived. Hopefully yours does too. But if it's new, you may be able to RMA it?

I would think a CPU could take a lot of abuse, nothing moving there. dropped a HDD about 3 feet on to ceramic tile an that HDD bought the farm, RMAed that sucker and all was well.