Data on a new drive is an unusual issue. Was it a refurbished drive? It's also possible that it's showing up that way because it hasn't been formatted yet. Either way, you can simply format the drive to fix that. (I also strongly recommend running chkdsk on any new drive)
As far as the total capacity listed in windows @465gb, that is normal.
1. A gigabyte, as counted on the label by HDD manufacturers, is 1 billion bytes. A gigabyte, as counted by computers, is 2^30, or 1,073,741,824 bytes. 1 label gigabyte will show up as 0.93GB in your OS. 465 is exactly 93% of 500.
2. You will lose a tiny bit more capacity when you format. "Typically, some of an HDD's capacity is unavailable to the user because it is used by the file system and the computer operating system, and possibly inbuilt redundancy for error correction and recovery."