I have the same problem as golorsky1 06-21-2010
I have 2 Hard drives.
Disk0 is 500Gb and partitioned into c:\, d:\ ,e:\ and f:\
Disk1 is 1Tb in one partition.
My Disk 0 (boot drive) doesn't show in device manager or disk management but shows in windows explorer,disk deframenter and Easeus Partition Master.
No malware shows on scans although a clunk sounds on bootup like something isn't being found.
Oh yeah, and it hangs when trying to start in safe mode.
I have no more ideas.
It's there because SATA by default allows "hot swapping" of drives. This paper from Microsoft describes how to edit the Registry to tell Windows that the drive should be treated as a non-removable device.
The thread doesn't exactly pertain to you, but the reply is about the "hot-swapping" feature.