HDD reduced by ? in Windows ME

A hard drive recently decreased in size by ? as seen in Windows. In Partition Magic however, it reports as usual. When cloning a recently saved image from CD-ROM Windows refused because the target was smaller than the source image. Formatting and Ghosting solved that problem, but unfortunately the saved image contains the same error (hard drive is half it?s normal size).

Has anyone experienced this and found a fix? The MS Knowledgebase contained no matches to various searches. I am contemplating upgrading to Windows 2000, thoughts?