Adding a second hard drive to VirtualBox is a very simple process, however you must remember to partition the new disk and assign it a drive letter. To perform this process, you need to follow the steps listed below.
1. Shut down the guest OS.
2. In VirtualBox, click the Storage button for the appropriate Virtual Machine.
3. Click the New button to create a new hard disk and create a new hard drive file via the wizard (a .vdi file).
4. Add the .vdi file you just created to be a hard drive for the guest OS by clicking the Add Attachment icon on the right and selecting your .vdi file in the file explorer from the drop down list that appears.
5. Choose IDE Primary Slave.
6. Next clcik Start to boot the Windows XP VM.
7. Go to Start –> Control Panel and choose Classic view.
8. Go to Administrative Tools –> Computer Management.
9. Under the Storage drop-down menu on the left, choose Disk Management.
10. A wizard should pop up to help you add the drive. You can either follow the wizard or perform the steps manually.
11. Right click on the newly added disk (it should say Unallocated) and choose New Volume.
12. Next right click again and choose Partition. Choose NTFS partitioning and the drive letter and click OK.
13. As soon as that process is complete, you can close out of Computer Management and you will see the new drive in Windows Explorer.
