Welcome to the community, lalalalong!
I'd suggest to try these commands using Command Prompt to see if that will fix the issue:
Go to the Start menu >
Type Run (as Administrator) > In the Run dialog, type cmd > type diskpart >
then list volume > then type select volume # (the volume number of your new internal HDD) >
write attributes disk clear readonly >
type X:>attrib -r /s /d (where X is the drive letter assigned to the HDD)
In case this doesn't work, check this tutorial with several other suggestions on how to resolve this:
http://www.wikihow.com/Disable-Write-Protection
Hope i helped! Good Luck!

SuperSoph_WD