Turning an external hard drive internal

Hey guys I've got a weird and probably really stupid question for you, I'm building a gaming rig this coming week and have had to dip out a bit on hard drive space. Previously I purchased a Seagate 1tb hard drive an i'm aware that you can turn internal hard drives external but can you do the reverse? If possible I want to make this 1tb HDD into an internal one.
Thanks all,
Jared

The hard drives inside external enclosures are standard drives. If you can get the case open, you can remove the drive from the case and use it in your machine.

The biggest risk you face is that the drive inside the case may not have the same interface type as your motherboard. For example, if you have a motherboard that only has SATA connectors and it turns out that the drive from your external case is an IDE drive, then you've got a problem.

If your external drive has an eSATA connector, you might just be able to use that to connect to your computer - it will have the same performance as an internal drive.