Have a look at Resizing a Virtual Disk for Windows Guests with Step by Step Instructions. Alternatives include adding a second hard disk or using Shared Folders for data files.

You have to shutdown the virtual machine first (i.e. Virtual machine > Shutdown Guest or so)

I had tried changing the drive with the guest shutdown but not with
the guest window still open. That did the trick. I may still go the
route of changing the drive size but at least now I have options.

Thank you for your help and quick response.