Using HP External Hard Drive as a Internal

[abablitz]

So I opened up my HP External Harddrive and tried to insert it into my Desktop and use it as a internal. It turned out to be a Western Digital 1tb Green Caviar.

Upon boot up it would not recognize the disk, so I went to Computer>Manage>Disk Management
It then asked me to convert my HD into a different file format so that it could be read. I did so, and upon doing so I still could not access the HD, and now it shows up as unpartiioned and it cannot be accessed using any computer.

However, I used a file recovery program to test it out, and the returned results suggest that none of the files have been deleted. I want to restore this as a external HD, how would I go around fixing this?

 

[abablitz]

I can't remember exactly the options but it had mbr and something that started with a G