What OS is on this Hitachi HDD?
If you have connected it to a working computer provided that the OS in the working computer can read the Partition it should just be there and scanable.
Of course if the OS on the Hitachi Drive is OSX, Linux or BSD it's not readable by a Windows OS most times unless you install software that allows to read that Partition Type.
If you have a Windows OS on your HDD like XP and the removed HDD has Vista or 7 it's possible that you have found a Formating Issue where your older installed Windows is unable to read a new Partition Form even though it's supposed to be the same Partition Type.
When M$ introduced Vista quite a few new drives where unreadable by working systems owing to new security measures that where introduced to NTFS Partitions and you needed to repartition the drive with the OS you where using. Generally this applied to Older versions of Windows being unable to read drives partitioned on newer versions of Windows.
If all you want to do is a AV/Malware Scan on this Hitachi Drive I would just use a Boot Disc like F Secure or any of the other that are available. Here is a TR Article on Rescue Disc's with links to the different ones available. ;)
https://www.techrepublic.com/blog/security/rescue-cds-tips-for-fighting-malware/3803
Col
